UPPBE2012RelayServerMain improvements.

- Added a test for missing arguments, printing usage when failed
Removed JSON library files from project


- added a project reference in .classpath to a clone of a fork
of JSON-java github repository
(https://github.com/sebastienjean/JSON-java.git)
Added Javadoc comments in UBPE2012RelayServerMain
Added javadoc comments to Stoppable
Added JavaDoc comments to DataEventListener
Added JavaDoc comments to AbstractDataEventListenerService
Added JavaDoc comments to AbstractFileBuilderDataEventListenerService
Modified JSonFilteredFilesProducerService to turn it more generic

- Tokens, output files names and fields number are now constructor
parameters