Change RevealJS paths to default folder structure of project

Using reveal.js/ pathing to javascript and css resources
to following pattern of other backends and simplifying
dependencying cloning for ADocs using this backend.
Fix default RevealJS stylesheet path
Added fragment step support for olist and ulist
Add block_image
initial cut at manpage backend in erb
Merge pull request #15 from jordanmccullough/revealjs-improvements

RevealJS paths to default, Fragment Step Support
add helpers for manpage backend
Merge pull request #18 from buuhsmead/master

Add block_image
Merge remote-tracking branch 'upstream/master' into sarah
next batch of overrides