Add duplicate button. Pass the costume ID to paint (the previous costume ID used matches when duplicate is used.) When switching to the costume tab, open the current costume.

* Implement paint-75: Add blank costume button

* add backdrop icon, use default name

thanks @fsih !

This is for https://github.com/LLK/scratch-paint/pull/194, making the selector area smaller on tablet so as to create more space for the paint editor

Keep localization in the container level. Ideally we should not be passing message descriptors.

Costumes and Sound tab strings.

With jscodeshift thank God

* Fix costume loading in sprite info pane

Requires LLK/scratch-vm#517

* Fix costume loading in costumes tab

Requires LLK/scratch-vm#517