Mavenize postfix and provide luna jdt feature patch

This patch creates the required maven structure to build an update site, and it also provides a feature patch for org.eclipse.jdt that integrates the patches from https://bugs.eclipse.org/bugs/show_bug.cgi?id=433500 - a first smoke test on a plain Eclipse Luna RCP did run through.

The proposed templates did not show up, afte re-configuring them, however, I was able to work with the postfix completion solution :)