Simplify pip installation instructions
Simplify pip installation instructions

There is no need to install kivy from github anymore after the release of 1.9.1
kived/kivy,matham/kivy,Cheaterman/kivy,rnixx/kivy,andnovar/kivy,akshayaurora/kivy,autosportlabs/kivy,manthansharma/kivy,jkankiewicz/kivy,vitorio/kivy,LogicalDash/kivy,inclement/kivy,rafalo1333/kivy,bionoid/kivy,Cheaterman/kivy,CuriousLearner/kivy,autosportlabs/kivy,kived/kivy,inclement/kivy,jkankiewicz/kivy,cbenhagen/kivy,jegger/kivy,janssen/kivy,janssen/kivy,andnovar/kivy,aron-bordin/kivy,kivy/kivy,CuriousLearner/kivy,cbenhagen/kivy,vitorio/kivy,inclement/kivy,autosportlabs/kivy,andnovar/kivy,LogicalDash/kivy,el-ethan/kivy,manthansharma/kivy,matham/kivy,kived/kivy,janssen/kivy,tony/kivy,darkopevec/kivy,jegger/kivy,jkankiewicz/kivy,rnixx/kivy,Cheaterman/kivy,kivy/kivy,akshayaurora/kivy,arlowhite/kivy,manthansharma/kivy,vitorio/kivy,LogicalDash/kivy,tony/kivy,darkopevec/kivy,darkopevec/kivy,arlowhite/kivy,arlowhite/kivy,jegger/kivy,manthansharma/kivy,rafalo1333/kivy,jegger/kivy,kivy/kivy,matham/kivy,bionoid/kivy,Cheaterman/kivy,bionoid/kivy,bionoid/kivy,LogicalDash/kivy,jkankiewicz/kivy,KeyWeeUsr/kivy,aron-bordin/kivy,aron-bordin/kivy,KeyWeeUsr/kivy,matham/kivy,cbenhagen/kivy,aron-bordin/kivy,rnixx/kivy,janssen/kivy,CuriousLearner/kivy,rafalo1333/kivy,KeyWeeUsr/kivy,KeyWeeUsr/kivy,akshayaurora/kivy,el-ethan/kivy,darkopevec/kivy,tony/kivy,el-ethan/kivy