JMS input plugin : First commit

Now includes jruby-jms gem in the contrib tarball

Needs code review from Logstash developpers and designers (see TODO notes in jms.rb)

	new file:   lib/logstash/inputs/jms.rb
	modified:   logstash-contrib.gemspec
Merge pull request #1 from damienclaveau/master

JMS input plugin : First commit
Removing requirements around queue/topic names.
Initial code for a JMS output.

Code for outputting from logstash to JMS. This builds up a producer for
every output so there is still work needed before its too useful.
Caching producer on output and new selector for input

Made changes so that a producers will be cached when using JMS for an
output. Also added the option to use a selector on an input. Also
adjusted tabbing which is why there are more changes.
Fix to have a default codec and to use codec internally. Will still grab JMS headers as well but will just add those to what the codec returns.