Change core for multiple enivornment setup

This is a slightly modified verision of the backbonejs pattern that works
with AMD, Node.js/CommonJS, and regular global browser exporting.
Only copy over core of highlight.js

There is no longer a need to build core of any environment as it does that
itself now.
Change index file template importing of core
Remove the need for AMD build condition
Change template task to new interface
Change browser build to use new template task
Add forgotten change from this to hljs
Remove unused amdArgs variable
Merge branch 'unified-core'