BUG-49753 Enhancement implemented

Implementation of BUG-47953 added.

The POM files are only designed to build mavenised artefacts, this does not replace the existing ANT build process at all.  This will create compiled jars and sources jars.  

The POM files are based on the ones uploaded to BUG-47953 and tweaked a bit to get them working with 2.5.1.

Would be nice to see this added in so we can get the jMeter atrefacts added to the main maven repo.