Fixed bug with Camera widget in .kv file
Fixed bug with Camera widget in .kv file

The resolution property is not initialized before _on_index() is called.
So the app crashes because [-1, -1] is not a supported resolution.

...
Camera:
    resolution: (640, 480)
    index: 0


hansent/kivy,wangjun/kivy,CuriousLearner/kivy,Shyam10/kivy,KeyWeeUsr/kivy,Davideddu/kivy-forkedtouch,bionoid/kivy,zennobjects/kivy,Davideddu/kivy-forkedtouch,rafalo1333/kivy,thezawad/kivy,eHealthAfrica/kivy,xpndlabs/kivy,jegger/kivy,autosportlabs/kivy,adamkh/kivy,edubrunaldi/kivy,kivatu/kivy-bak,arcticshores/kivy,angryrancor/kivy,dirkjot/kivy,kived/kivy,gonzafirewall/kivy,habibmasuro/kivy,bob-the-hamster/kivy,VinGarcia/kivy,Ramalus/kivy,cbenhagen/kivy,rnixx/kivy,xpndlabs/kivy,Cheaterman/kivy,arcticshores/kivy,kivatu/kivy-bak,xiaoyanit/kivy,ernstp/kivy,arlowhite/kivy,KeyWeeUsr/kivy,dirkjot/kivy,bhargav2408/kivy,MiyamotoAkira/kivy,janssen/kivy,jffernandez/kivy,yoelk/kivy,bliz937/kivy,VinGarcia/kivy,wangjun/kivy,gonzafirewall/kivy,Farkal/kivy,inclement/kivy,niavlys/kivy,rafalo1333/kivy,JohnHowland/kivy,cbenhagen/kivy,darkopevec/kivy,inclement/kivy,hansent/kivy,manthansharma/kivy,xiaoyanit/kivy,mSenyor/kivy,matham/kivy,aron-bordin/kivy,manthansharma/kivy,jehutting/kivy,jffernandez/kivy,ehealthafrica-ci/kivy,jegger/kivy,vitorio/kivy,KeyWeeUsr/kivy,LogicalDash/kivy,bionoid/kivy,kivy/kivy,jffernandez/kivy,jkankiewicz/kivy,autosportlabs/kivy,angryrancor/kivy,jkankiewicz/kivy,adamkh/kivy,vipulroxx/kivy,LogicalDash/kivy,manthansharma/kivy,dirkjot/kivy,LogicalDash/kivy,Davideddu/kivy-forkedtouch,eHealthAfrica/kivy,MiyamotoAkira/kivy,hansent/kivy,bhargav2408/kivy,bob-the-hamster/kivy,el-ethan/kivy,zennobjects/kivy,andnovar/kivy,ernstp/kivy,aron-bordin/kivy,manashmndl/kivy,youprofit/kivy,iamutkarshtiwari/kivy,xiaoyanit/kivy,tony/kivy,kived/kivy,ernstp/kivy,arcticshores/kivy,Ramalus/kivy,denys-duchier/kivy,edubrunaldi/kivy,denys-duchier/kivy,jehutting/kivy,niavlys/kivy,bob-the-hamster/kivy,hansent/kivy,bliz937/kivy,Shyam10/kivy,janssen/kivy,kivatu/kivy-bak,viralpandey/kivy,yoelk/kivy,tony/kivy,eHealthAfrica/kivy,Cheaterman/kivy,kived/kivy,vipulroxx/kivy,eHealthAfrica/kivy,cbenhagen/kivy,gonzafirewall/kivy,janssen/kivy,Shyam10/kivy,Davideddu/kivy-forkedtouch,akshayaurora/kivy,matham/kivy,viralpandey/kivy,wangjun/kivy,bhargav2408/kivy,niavlys/kivy,habibmasuro/kivy,rafalo1333/kivy,el-ethan/kivy,JohnHowland/kivy,thezawad/kivy,youprofit/kivy,rnixx/kivy,bob-the-hamster/kivy,MiyamotoAkira/kivy,niavlys/kivy,adamkh/kivy,Cheaterman/kivy,Farkal/kivy,xpndlabs/kivy,ehealthafrica-ci/kivy,dirkjot/kivy,vitorio/kivy,LogicalDash/kivy,thezawad/kivy,manashmndl/kivy,darkopevec/kivy,youprofit/kivy,adamkh/kivy,aron-bordin/kivy,angryrancor/kivy,jehutting/kivy,aron-bordin/kivy,mSenyor/kivy,KeyWeeUsr/kivy,yoelk/kivy,MiyamotoAkira/kivy,ernstp/kivy,angryrancor/kivy,rnixx/kivy,tony/kivy,iamutkarshtiwari/kivy,edubrunaldi/kivy,ehealthafrica-ci/kivy,JohnHowland/kivy,arlowhite/kivy,vipulroxx/kivy,Shyam10/kivy,vipulroxx/kivy,kivy/kivy,jegger/kivy,JohnHowland/kivy,kivy/kivy,jffernandez/kivy,jegger/kivy,habibmasuro/kivy,bliz937/kivy,manashmndl/kivy,gonzafirewall/kivy,andnovar/kivy,viralpandey/kivy,akshayaurora/kivy,wangjun/kivy,darkopevec/kivy,darkopevec/kivy,CuriousLearner/kivy,arcticshores/kivy,ehealthafrica-ci/kivy,Farkal/kivy,jkankiewicz/kivy,zennobjects/kivy,Farkal/kivy,matham/kivy,Ramalus/kivy,jkankiewicz/kivy,VinGarcia/kivy,akshayaurora/kivy,denys-duchier/kivy,iamutkarshtiwari/kivy,vitorio/kivy,el-ethan/kivy,bionoid/kivy,zennobjects/kivy,yoelk/kivy,mSenyor/kivy,andnovar/kivy,kivatu/kivy-bak,inclement/kivy,janssen/kivy,CuriousLearner/kivy,denys-duchier/kivy,autosportlabs/kivy,bionoid/kivy,Cheaterman/kivy,manthansharma/kivy,arlowhite/kivy,matham/kivy