Improved ReqireJS Handling

* The webjar! plugin loader works again (when possible)
* The RequireJS meta-data can now be pulled from the pom.xml so everything is in one place
* A new JSON API for getting the RequireJS config makes it easier to work with structured JSON data and fits better with the non-JavaScript JSON that RequireJS uses for config
cleanup
Merge pull request #47 from webjars/fix/half-sensible-requirejs

Improved ReqireJS Handling