Add WebJars support

[WebJars](http://www.webjars.org) are client-side web libraries packaged into JAR (Java Archive) files.

This new feature would allow any JavaEE application (using Servlet API >= 3.0) to easily user the LDF Javascript client.

The background of this PR is the [support we're including in Apache Marmotta](http://markmail.org/message/ayw3q4vwuhgflass). This, in combination with having the artifact available from Maven Central due ASF rules (I can also help on that), would make the integration quite easy for us.