Remove Ruby 2.0.0 from TravisCI matrix.
Remove Ruby 2.0.0 from TravisCI matrix.

Fixes #4381.

jeffkole/jekyll,brint/jekyll,derekgottlieb/jekyll,darwin/jekyll,getandpost/jekyll.github.io,floydpraveen/jekyll,pmarsceill/jekyll,rlugojr/jekyll,jaybe-jekyll/jekyll,Kinghack/kinghack.github.com,ryanshaw/jekyll,nasht00/jekyll,stomar/jekyll,fulldecent/jekyll,jekyll/jekyll,gencer/jekyll,chrisfinazzo/jekyll,alex-kovac/jekyll,Strangehill/jekyll,rlugojr/jekyll,derekgottlieb/jekyll,tillgrallert/jekyll,ZDroid/jekyll,chrisfinazzo/jekyll,xcatliu/jekyllcn,x-way/jekyll,jaybe-jekyll/jekyll,noikiy/jekyll,tillgrallert/jekyll,rasa2011/rasa2011.github.io,jeffkole/jekyll,floydpraveen/jekyll,alfredxing/jekyll,brint/jekyll,Strangehill/jekyll,fulldecent/jekyll,tillgrallert/jekyll,nasht00/jekyll,jeffkole/jekyll,ryanshaw/jekyll,alfredxing/jekyll,xiebinhqy/jklly_china,Strangehill/jekyll,yhironaka/yhironaka.github.io,derekgottlieb/jekyll,darwin/jekyll,stomar/jekyll,pmarsceill/jekyll,stomar/jekyll,floydpraveen/jekyll,noikiy/jekyll,rlugojr/jekyll,jaybe-jekyll/jekyll,rasa2011/rasa2011.github.io,x-way/jekyll,nasht00/jekyll,brint/jekyll,x-way/jekyll,darwin/jekyll,fulldecent/jekyll,jaybe-jekyll/jekyll,gencer/jekyll,jekyll/jekyll,noikiy/jekyll,tomjohnson1492/jekyll,gencer/jekyll,nasht00/jekyll,tillgrallert/jekyll,tomjohnson1492/jekyll,jeffkole/jekyll,x-way/jekyll,tomjohnson1492/jekyll,ryanshaw/jekyll,xiebinhqy/jklly_china,gencer/jekyll,xiebinhqy/jklly_china,xcatliu/jekyllcn,tillgrallert/jekyll,fulldecent/jekyll,xiebinhqy/jklly_china,ZDroid/jekyll,jekyll/jekyll,Kinghack/kinghack.github.com,getandpost/jekyll.github.io,stomar/jekyll,pmarsceill/jekyll,ajhit406/jekyll,chrisfinazzo/jekyll,alex-kovac/jekyll,ajhit406/jekyll,Strangehill/jekyll,tomjohnson1492/jekyll,alex-kovac/jekyll,jekyll/jekyll,derekgottlieb/jekyll,alex-kovac/jekyll,darwin/jekyll,tomjohnson1492/jekyll,gencer/jekyll,rasa2011/rasa2011.github.io,brint/jekyll,pmarsceill/jekyll,xcatliu/jekyllcn,getandpost/jekyll.github.io,noikiy/jekyll,ajhit406/jekyll,alfredxing/jekyll,rlugojr/jekyll,alex-kovac/jekyll,xcatliu/jekyllcn,floydpraveen/jekyll,alfredxing/jekyll,ZDroid/jekyll,ryanshaw/jekyll,Kinghack/kinghack.github.com,Strangehill/jekyll,chrisfinazzo/jekyll,ajhit406/jekyll