Adds toc flag to Book.

This flag will display a table of contents within the book output when
set to true.
Adds table of contents generation.
Adds HTMLSupervisor to use as a controller for generation.

Adds tests for generator. Mocha really doesn't handle blocks all that
well.
Moves helpers to HTMLSupervisor and updates views to use HTMLSupervisor.
Adds Asset: asset management and copying class.
Adds Style class: manages style information and associated assets.
Adds missing documentation to HTMLSupervisor.
Adds common style assets.
Adds css to Basic style.
Adds the use of Style to Book class.

It now will create a Style for the style listed for use in generating
the book from either the argument passed in, the yaml file, or "basic"
default when all else fails.