Fix header for RSS feeds with UTF8 characters.
Fix header for RSS feeds with UTF8 characters.

```
$ curl http://localhost:4000/feed.xml -I
HTTP/1.1 200 OK
Etag: 64af8c-2356-552805aa
Content-Type: text/xml; charset=utf-8
Content-Length: 9046
Last-Modified: Fri, 10 Apr 2015 17:17:30 GMT
Server: WEBrick/1.3.1 (Ruby/2.2.1/2015-02-26)
Date: Fri, 10 Apr 2015 17:17:34 GMT
Connection: Keep-Alive
```

Originally contributed to https://github.com/fitztrev/jekyll-utf8/pull/3
CorainChicago/jekyll,ReachingOut/jekyll,xcatliu/jekyllcn,richsoni/jekyll,thetaxman/jekyll,ZDroid/jekyll,Teino1978-Corp/jekyll,likong/jekyll,dezon/jekyll,xiongjungit/jekyll,ryanshaw/jekyll,jmptrader/jekyll,UniFreak/jekyllcn,fengsmith/jekyllcn,Kinghack/kinghack.github.com,isathish/jekyll,xtymichael/jekyll,gencer/jekyll,mixxmac/jekyll,adilapapaya/jekyll,teju111/jekyll,xantage/jekyll,LeuisKen/jekyllcn,codeclimate-testing/jekyll,AtekiRyu/jekyll,mixxmac/jekyll,gynter/jekyll,chrisfinazzo/jekyll,CorainChicago/jekyll,mrb/jekyll,pheuko/jekyll,Tyrion22/jekyll,codeclimate-testing/jekyll,xtymichael/jekyll,pmarsceill/jekyll,nickg33/jekyll,pmarsceill/jekyll,larryfox/jekyll,rasa2011/rasa2011.github.io,CPVPLachlan/CPVP-Blog,UniFreak/jekyllcn,tobscure/jekyll,doubleday/jekyll,QuinntyneBrown/jekyll,derekgottlieb/jekyll,alfredxing/jekyll,mrb/jekyll,honger05/jekyllcn,teju111/jekyll,iRoxx/jekyll,xiongjungit/jekyll,0x00evil/jekyll,abhilashhb/jekyll,ls2uper/jekyll,egobrightan/jekyll,liukaijv/jekyll,tylermachen/jekyll,QuinntyneBrown/jekyll,chiyodad/jekyll,gynter/jekyll,larryfox/jekyll,imaustink/jekyll,ramoslin02/jekyll,princeofdarkness76/jekyll,saitodisse/jekyll,floydpraveen/jekyll,rasa2011/rasa2011.github.io,eloyesp/jekyll,oresmus/jekyll,bsmr-ruby/jekyll,backendeveloper/jekyll,ducktyper/jekyll,garvitr/jekyll,tamouse/jekyll,LuoPX-15510486969/jekyll,royalwang/jekyll,krishnakalyan3/jekyll,jaroot32/jekyll,penchan1218/jekyllcn,martynbm/jekyll,yihangho/jekyll,vidbina/jekyll,eloyesp/jekyll,supriyantomaftuh/jekyll,tomasdiez/jekyll,chrisfinazzo/jekyll,ZDroid/jekyll,aarvay/jekyll,likong/jekyll,ajhit406/jekyll,zhangkuaiji/jekyllcn,zsyed91/jekyll,rlugojr/jekyll,Wirachmat/jekyll,noikiy/jekyll,christophermanning/jekyll,fabulousu/jekyll,tylermachen/jekyll,penchan1218/jekyllcn,alex-kovac/jekyll,harrissoerja/jekyll,omeripek/jekyll,ZainRizvi/jekyll,xiaoshaozi52/jekyll,MjAbuz/jekyll,iRoxx/jekyll,jmhardison/jekyll,krahman/jekyll,jekyll/jekyll,zhangkuaiji/jekyllcn,harrissoerja/jekyll,tamouse/jekyll,jmepg/jekyll,oresmus/jekyll,cyberid41/jekyll,gencer/jekyll,stomar/jekyll,wentixiaogege/jekyll,imaustink/jekyll,FlyingWHR/jekyll,jmhardison/jekyll,chiyodad/jekyll,xiebinhqy/jklly_china,derekgottlieb/jekyll,nasht00/jekyll,CheekyFE/jekyll,matuzo/jekyll,Tiger66639/jekyll,CPVPLachlan/CPVP-Blog,brint/jekyll,Teino1978-Corp/Teino1978-Corp-jekyll,harrissoerja/jekyll,yihangho/jekyll,goragod/jekyll,julienbourdeau/jekyll,xiongjungit/jekyll,honger05/jekyllcn,fabulousu/jekyll,leichunxin/jekyll,EddieDow/jekyll,tillgrallert/jekyll,liukaijv/jekyll,LeuisKen/jekyllcn,martynbm/jekyll,AtekiRyu/jekyll,kuangyeheng/jekyll,xcatliu/jekyllcn,dansef/jekyll,htmelvis/jekyll,goragod/jekyll,QuinntyneBrown/jekyll,thejameskyle/jekyll,mrb/jekyll,AaronSikes/jekyll,chrisfinazzo/jekyll,jeffkole/jekyll,ewinkler/jekyll,derekgottlieb/jekyll,eninya/jekyll,nateberkopec/jekyll,anthonyrosengren/grasshoppergathering2.github-io,wadaries/jekyll,hubsaysnuaa/jekyll,ZainRizvi/jekyll,trungvothanh/jekyll,PepSalehi/jekyll,nickg33/jekyll,m2candre/jekyll,gencer/jekyll,darwin/jekyll,howkj1/jekyll,howkj1/jekyll,jmknoll/jekyll,xiebinhqy/jklly_china,tugberkugurlu/jekyll,rovrevik/jekyll,wadaries/jekyll,gkunwar/gkunwar.github.io,fulldecent/jekyll,liukaijv/jekyll,noikiy/jekyll,jekyll/jekyll,derekgottlieb/jekyll,x-way/jekyll,daniel-beck/jekyll,18F/jekyll,alex-kovac/jekyll,fengsmith/jekyll,rongl/jekyll,tomjohnson1492/jekyll,hiteshsuthar/jekyll,MauroMrod/jekyll,AtekiRyu/jekyll,brint/jekyll,jmepg/jekyll,trungvothanh/jekyll,howkj1/jekyll,matuzo/jekyll,saitodisse/jekyll,chinayin/jekyll,ajhit406/jekyll,alfredxing/jekyll,foocoder/jekyll,royalwang/jekyll,Tiger66639/jekyll,ducktyper/jekyll,hubsaysnuaa/jekyll,winndows/jekyll,ramoslin02/jekyll,alfredxing/jekyll,desidude03/jekyll,jmepg/jekyll,jekyll/jekyll,rlugojr/jekyll,cyberid41/jekyll,tylermachen/jekyll,rajrathore/jekyll,hiteshsuthar/jekyll,x-way/jekyll,chrisfinazzo/jekyll,cyberid41/jekyll,supriyantomaftuh/jekyll,eninya/jekyll,oresmus/jekyll,tomasdiez/jekyll,digideskio/jekyll,ZDroid/jekyll,garvitr/jekyll,CPVPLachlan/CPVP-Blog,tobscure/jekyll,jeffkole/jekyll,Teino1978-Corp/jekyll,Kinghack/kinghack.github.com,marrujoalex/jekyll,superve/jekyll,sasongkojati/jekyll,tamouse/jekyll,greent2008/jekyll,rajrathore/jekyll,rovrevik/jekyll,getandpost/jekyll.github.io,Strangehill/jekyll,penchan1218/jekyllcn,sanxore/sanxore.github.com,tillgrallert/jekyll,m2candre/jekyll,rlugojr/jekyll,hubsaysnuaa/jekyll,dansef/jekyll,zsyed91/jekyll,gaosboy/jekyll,PepSalehi/jekyll,LuoPX-15510486969/jekyll,krishnakalyan3/jekyll,isathish/jekyll,Teino1978-Corp/jekyll,desidude03/jekyll,x-way/jekyll,mrb/jekyll,0x00evil/jekyll,isathish/jekyll,pmarsceill/jekyll,ramoslin02/jekyll,Wirachmat/jekyll,thetaxman/jekyll,darwin/jekyll,dansef/jekyll,shliujing/jekyll,desidude03/jekyll,johnnycastilho/jekyll,sasongkojati/jekyll,rongl/jekyll,alihalabyah/jekyll,ZainRizvi/jekyll,0x00evil/jekyll,Teino1978-Corp/Teino1978-Corp-jekyll,kimeng/jekyll,tareq-s/jekyll,gencer/jekyll,codeclimate-testing/jekyll,CheekyFE/jekyll,hiteshsuthar/jekyll,fulldecent/jekyll,krahman/jekyll,gkunwar/gkunwar.github.io,angeliaz/jekyll,nemotan/jekyll,egobrightan/jekyll,omeripek/jekyll,sanxore/sanxore.github.com,fengsmith/jekyll,zsyed91/jekyll,foocoder/jekyll,yhironaka/yhironaka.github.io,shliujing/jekyll,daniel-beck/jekyll,princeofdarkness76/jekyll,noikiy/jekyll,LuoPX-15510486969/jekyll,SQS2/Test,gaosboy/jekyll,bsmr-ruby/jekyll,drobati/jekyll,naughtyboy83/jekyll,richsoni/jekyll,anthonyrosengren/grasshoppergathering2.github-io,wentixiaogege/jekyll,thejameskyle/jekyll,MauroMrod/jekyll,rebornix/jekyll,jmknoll/jekyll,MauroMrod/jekyll,alex-kovac/jekyll,jaybe-jekyll/jekyll,MjAbuz/jekyll,kimeng/jekyll,backendeveloper/jekyll,ewinkler/jekyll,Teino1978-Corp/Teino1978-Corp-jekyll,johnnycastilho/jekyll,jaybe-jekyll/jekyll,gkunwar/gkunwar.github.io,leichunxin/jekyll,honger05/jekyllcn,rebornix/jekyll,MjAbuz/jekyll,tillgrallert/jekyll,shuber2/jekyll,AnanthaRajuC/jekyll,CheekyFE/jekyll,tobscure/jekyll,floydpraveen/jekyll,xiaoshaozi52/jekyll,kimeng/jekyll,AnanthaRajuC/jekyll,tomjohnson1492/jekyll,tareq-s/jekyll,greent2008/jekyll,teju111/jekyll,noikiy/jekyll,AnanthaRajuC/jekyll,dezon/jekyll,18F/jekyll,digideskio/jekyll,brint/jekyll,zsyed91/jekyll,pheuko/jekyll,FlyingWHR/jekyll,Strangehill/jekyll,jaroot32/jekyll,anthonyrosengren/grasshoppergathering2.github-io,backendeveloper/jekyll,vcgato29/jekyll,goragod/jekyll,dezon/jekyll,bsmr-ruby/jekyll,egobrightan/jekyll,Strangehill/jekyll,krishnakalyan3/jekyll,gynter/jekyll,stomar/jekyll,pheuko/jekyll,jaybe-jekyll/jekyll,kuangyeheng/jekyll,sanxore/sanxore.github.com,jmhardison/jekyll,Tyrion22/jekyll,jaroot32/jekyll,jmptrader/jekyll,hartmel/jekyll,jmptrader/jekyll,drobati/jekyll,ReachingOut/jekyll,abhilashhb/jekyll,tugberkugurlu/jekyll,alihalabyah/jekyll,tomjohnson1492/jekyll,18F/jekyll,marrujoalex/jekyll,christophermanning/jekyll,stomar/jekyll,matuzo/jekyll,x-way/jekyll,thetaxman/jekyll,abhilashhb/jekyll,foocoder/jekyll,AaronSikes/jekyll,xcatliu/jekyllcn,nasht00/jekyll,fengsmith/jekyllcn,nemotan/jekyll,rovrevik/jekyll,Wirachmat/jekyll,tomasdiez/jekyll,johnnycastilho/jekyll,FlyingWHR/jekyll,Strangehill/jekyll,alex-kovac/jekyll,shuber2/jekyll,leichunxin/jekyll,Strangehill/jekyll,stomar/jekyll,htmelvis/jekyll,eninya/jekyll,rongl/jekyll,angeliaz/jekyll,vcgato29/jekyll,marrujoalex/jekyll,aarvay/jekyll,nasht00/jekyll,naughtyboy83/jekyll,ajhit406/jekyll,SQS2/Test,alex-kovac/jekyll,xantage/jekyll,ryanshaw/jekyll,darwin/jekyll,wentixiaogege/jekyll,greent2008/jekyll,LeuisKen/jekyllcn,ducktyper/jekyll,chinayin/jekyll,mixxmac/jekyll,naughtyboy83/jekyll,floydpraveen/jekyll,jeffkole/jekyll,vidbina/jekyll,imaustink/jekyll,indraj/jekyll,xiebinhqy/jklly_china,tugberkugurlu/jekyll,ReachingOut/jekyll,vidbina/jekyll,ajhit406/jekyll,kuangyeheng/jekyll,princeofdarkness76/jekyll,digideskio/jekyll,AaronSikes/jekyll,CorainChicago/jekyll,vcgato29/jekyll,xantage/jekyll,winndows/jekyll,jaybe-jekyll/jekyll,rajrathore/jekyll,christophermanning/jekyll,omeripek/jekyll,nasht00/jekyll,chiyodad/jekyll,xtymichael/jekyll,tomjohnson1492/jekyll,nemotan/jekyll,EddieDow/jekyll,martynbm/jekyll,iRoxx/jekyll,ryanshaw/jekyll,princeofdarkness76/jekyll,rlugojr/jekyll,tillgrallert/jekyll,hartmel/jekyll,tillgrallert/jekyll,krahman/jekyll,doubleday/jekyll,adilapapaya/jekyll,sasongkojati/jekyll,Tyrion22/jekyll,nateberkopec/jekyll,doubleday/jekyll,fulldecent/jekyll,drobati/jekyll,julienbourdeau/jekyll,aarvay/jekyll,floydpraveen/jekyll,bsmr-ruby/jekyll,eloyesp/jekyll,saitodisse/jekyll,larryfox/jekyll,m2candre/jekyll,Kinghack/kinghack.github.com,indraj/jekyll,fabulousu/jekyll,daniel-beck/jekyll,getandpost/jekyll.github.io,garvitr/jekyll,chinayin/jekyll,zhangkuaiji/jekyllcn,likong/jekyll,adilapapaya/jekyll,nickg33/jekyll,thejameskyle/jekyll,ewinkler/jekyll,superve/jekyll,superve/jekyll,brint/jekyll,xiebinhqy/jklly_china,getandpost/jekyll.github.io,indraj/jekyll,darwin/jekyll,gaosboy/jekyll,winndows/jekyll,xcatliu/jekyllcn,ryanshaw/jekyll,SQS2/Test,wadaries/jekyll,jeffkole/jekyll,PepSalehi/jekyll,jekyll/jekyll,angeliaz/jekyll,rebornix/jekyll,tareq-s/jekyll,jmknoll/jekyll,fengsmith/jekyll,supriyantomaftuh/jekyll,alihalabyah/jekyll,rasa2011/rasa2011.github.io,fulldecent/jekyll,EddieDow/jekyll,UniFreak/jekyllcn,Tiger66639/jekyll,pmarsceill/jekyll,richsoni/jekyll,gencer/jekyll,shliujing/jekyll,alfredxing/jekyll,fengsmith/jekyllcn,yihangho/jekyll,trungvothanh/jekyll,julienbourdeau/jekyll,shuber2/jekyll,hartmel/jekyll,ls2uper/jekyll,ls2uper/jekyll,xiaoshaozi52/jekyll,htmelvis/jekyll,nateberkopec/jekyll,royalwang/jekyll,tomjohnson1492/jekyll