1. Don't need 'video' tab in /new
2. Move #addSequence from NewController to NewRoute
3. Create and use ValidationMixin for Deck and Video
don't use sendAction to set deck and video players
Move Deck and Video validation messages to component
Refactor Decks
Add #set to ModelProxyMixin
1. /new - Deck and Video do all validations instead of controller
2. expand ValidationMixin for use by Deck and Video
3. use dynamic mixing for Deck and Video subtypes