Finished format protocol integration. For entire codebase.

MILESTONE: you should now use format() for all formatting needs.

MODEL: format() formats its object in the way you are most likely to want.
Calling format(component) returns the LilyPond format of the component;
calling format(scheme) returns the Lilypond format of the Scheme expression;
calling format() of most other objects returns the storage format of the
object.

The 'lilypond_format' property no longer appears anywhere in the codebase.

The 'storage_format' property no longer appears anywhere in the codebase.