A few changes.

* changed BannerView to general ExtraView
* added ImageKey
* added input traits polling extension
* fixed key cap behavior at init
* added another extendable method
Preparation for settings view.
Oops, forgot to commit this.

Updates appearance for dark mode.
Removed some cruft.
Oops, forgot to commit this as well.

Key appearance changes now handled better.
Updated readme.
Fixed banner superclass error.
Added proto Settings key and layout.
Added media assets.
Settings icon looks ok now.
Settings toggle works.
Settings view seems to work.
Fixed up catboard.
Better appearance for settings.
Settings now work correctly.
Enabled sounds.
Bundle resource fix.
Disabled vibrancy for now.
Performance improvements re: settings icon & shapes.
Better hosting app view.