Make id default to name if absent
Add a onepage_toc handler
Merge branch 'dev/onepage_toc' of github.com:raphink/showoff into raphink-dev/onepage_toc

Conflicts:
	lib/showoff.rb
Added TOC tag for building table of contents

Add a slide with a class of 'toc' and include the tag `~~~TOC~~~` and it
will be replaced with a programatically generated table of contents.

The TOC is generated in `onepage` view only.
Merge pull request #71 from binford2k/raphink-dev/onepage_toc

Customizable table of contents