CSS in a single file

Themes can then be implemented by simply overriding the default colors,
instead of trying to define universal styles and generic styles that are
difficult to separate and maintain.
No message styling

Messages are no longer used in the application.
Unnecessary rule removed
More unnecessary rules removed
Attribute-based bindings
Merge branch 'master' into refactor
Merge branch 'css' into refactor
Stage factored into Ambience Stage library
Media arrays are not serialized

These were previously serialized because Knockwrap incorrectly copied
getters returning arrays.
Old debug command removed
Polyfills in tabs are working

Due to some error either in Knockout, in jQuery, or in Attribute
Bindings that prevented polyfills from properly working, the data
contexts of the tabs were removed.
"afterkeydown" trigger reinstated
Simplified bindings
Scene detail views are hidden instead of removed

This should improve performance.
Start/stop bug fixed
IE10 styling tweaks
IE10 support note
Lazy media loading
Reliable media saving

Fixes #23.
No context-specific debug function