Restructure & add TOCs to more places.

Add table of contents to the Components, Helpers and Behaviors pages.
These pages currently make the list of core features harder to find than
they should be.

Adjust the existing TOC's to require less maintenance in the future and
include fewer irrelevant results (empty toc pages).
Restore old manually sorted TOC sections.

Move content so toc-XX pages aren't just stub chapters.
Re-use toc lists so we don't have to maintain two sets of tocs.
Update TOC to be ordered by frequency of use.

Also remove the deprecated email component from the toc list.
Exclude files to reduce whining.

Sphinx whine when files aren't in the TOC's exclude a few to shut it up.
Fix broken formatting.
Merge pull request #747 from cakephp/restructure-tocs

Restructure & add TOCs to more places.