Remove `_oldIE` variable.
Remove `_oldIE` variable.

* No need for `_oldIE` when we can just use `this.iframe`.
* Added `this._hasHashchange`.

nvoron23/backbone,braddunbar/backbone,yuhualingfeng/backbone,cailong1028/backbone,nvoron23/backbone,platinumazure/backbone,ppker/backbone,closeio/backbone,jewsroch/backbone,gmaclennan/backbone,darrrk/backbone,anhtholee/backbone,sunday-star/backbone,alekskorolev/lightbones,streamablevideo/backbone,paulfalgout/backbone,anhtholee/backbone,tibic/backbone,vin100bk/backbone,jmeas/backbone,zhangwei001/backbone,IsoldaJS/isolda-models,ThiagoGarciaAlves/backbone,feychenie/backbone,IsoldaJS/isolda-pubsub,guigrpa/backbone,tgriesser/backbone,vincent1988/backbone,au-phiware/backbone,leimd/backbone,wushuyi/backbone,ridixcr/backbone,rashmisajjan/backbone,yuhualingfeng/backbone,guahanweb/backbone,pandoraui/backbone,gougouGet/backbone,sumyfly/backbone,yawenl/backbone,wjb12/backbone,jordansexton/backboner,craigmichaelmartin/backbone,darrrk/backbone,oss-practice/backbone,jasoncbautista/backboneX,rashmisajjan/backbone,JesseQin/backbone,jungjung917/backbone,cailong1028/backbone,npmcomponent/jashkenas-backbone,jridgewell/backbone,chyeh727/backbone,Diwahars/backbone,premkumargithub/backbone,youprofit/backbone,tadwhitaker/backbone,dak/backbone,Diwahars/backbone,sunday-star/backbone,ereddate/backbone,moimikey/backbone,elancom/backbone,ntgn81/backbone,lujocom/backbone,leimd/backbone,Sachin-Ganesh/backbone,zhangwei001/backbone,FormidableLabs/backbone,tadwhitaker/backbone,lastjune/backbone,Connectlegendary/backbone,wangdahoo/backbone,gitterHQ/backbone,embarknow/backbone,gmaclennan/backbone,howtolearntocode/backbone,linalu1/backbone,sumyfly/backbone,cgvarela/backbone,zhoufan879/backbone,kuychaco/backbone,platinumazure/backbone,aihua/backbone,neocotic/hipbone,sueyeh/backbone,ohbarye/backbone,DannyDelott/backbone,Niades/backbone,dak/backbone,neocotic/hipbone,Bug2014/backbone,premkumargithub/backbone,zhoufan879/backbone,timebackzhou/backbone,sueyeh/backbone,zhangdimelody/backbone,fanhc019/backbone,closeio/backbone,huanglp47/backbone,jungjung917/backbone,Flip120/backbone,nikolas/backbone,zgl2007dj/backbone,liudianpeng/backbone,amitpatange88/backbonejs,Bug2014/backbone,elma-cao/backbone,GrimDerp/backbone,vincent1988/backbone,howtolearntocode/backbone,Niades/backbone,dcheepurupalli/backbone,wxmfront/backbone,FishbaitHarry/backbone,timebackzhou/backbone,udhayam/backbone,ohbarye/backbone,Krasnyanskiy/backbone,sitexa/backbone,dcheepurupalli/backbone,Krasnyanskiy/backbone,heroazure/backbone,zdespolit/backbone,chyeh727/backbone,FishbaitHarry/backbone,megawac/backbone,jashkenas/backbone,rjz/boneless,getshuvo/backbone,webcoding/backbone,tzkKrbys/backbone,jmeas/backbone,elma-cao/backbone,trizko/backbone,gdi2290/backbone,Sachin-Ganesh/backbone,tzkKrbys/backbone,akre54/backbone,streamablevideo/backbone,webcoding/backbone,elancom/backbone,mrblueblue/backbone,wangcan2014/backbone,zgl2007dj/backbone,youprofit/backbone,Connectlegendary/backbone,moimikey/backbone,ywenjinlin/backbone,vin100bk/backbone,akre54/backbone,ereddate/backbone,wjb12/backbone,wxmfront/backbone,jashkenas/backbone,hugohua/backbone,tibic/backbone,jridgewell/backbone,liudianpeng/backbone,amitpatange88/backbonejs,au-phiware/backbone,ywenjinlin/backbone,udhayam/backbone,feychenie/backbone,moccen/backbone,JesseQin/backbone,sitexa/backbone,yawenl/backbone,heroazure/backbone,braddunbar/backbone,paulfalgout/backbone,linalu1/backbone,zdespolit/backbone,jewsroch/backbone,mrblueblue/backbone,ridixcr/backbone,guahanweb/backbone,alekskorolev/lightbones,lujocom/backbone,wangdahoo/backbone,ppker/backbone,wushuyi/backbone,nikolas/backbone,huanglp47/backbone,DannyDelott/backbone,fanhc019/backbone,zhangdimelody/backbone,ntgn81/backbone,gougouGet/backbone,moccen/backbone,embarknow/backbone,trizko/backbone,ThiagoGarciaAlves/backbone,aihua/backbone,7213/backbone,craigmichaelmartin/backbone,7213/backbone,kuychaco/backbone,lastjune/backbone,pandoraui/backbone,GrimDerp/backbone,getshuvo/backbone,cgvarela/backbone,Flip120/backbone,wangcan2014/backbone