Make background drawable nullable
Make background drawable nullable

make `View.backgroundDrawable` nullable
Kotlin/anko,deva666/anko,JetBrains/anko,JetBrains/anko,Kotlin/anko,fboldog/anko,deva666/anko,deva666/anko,JetBrains/anko,fboldog/anko,fboldog/anko,Kotlin/anko