gem bundling refactor

update jruby jar to 1.7.15

pinned i18n dependency and cosmetic cleanups

new generated Gemfile lock

refactor gem bundling using stadalone setup & use standard Gemfile with gemspec

update to jruby 1.7.16 and remove jar-dependencies, bouncy-castle-java, jruby-openssl from gemspec

get ready for future plugins mechanism

Conflicts:
	logstash.gemspec