Readme: update Neo4j installation instructions.

To use Neo4j 1.8.2, and to symlink and gitignore it.
Simplify build; precompile to JS on publish now.

Fixes #35 also (installing on Heroku with Node 0.10).

I had originally considered this and went with compile-on-install so that
the CoffeeScript and Streamline compiler dependencies could be treated like
other dependencies -- use the best matching version at installation time
instead of effectively "freezing" those dependencies by compiling at publish
time -- but it seems this does simplify things. One less moving part at
deploy time for users. I can dig that.

Thanks @flipside for the nudge!