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