Add gitter IM link
Prepare for the next releases, 2.1.0, which will go as soon as tests are cleaned up
Make the gem installation directory configurable via jruby.gemInstallDir

Fixes #18
Update the README to reference the current minor version
Rename jruby.gemrepo_url to jruby.defaultGemRepo before anybody notices
Merge branch 'master' of https://github.com/rtyler/jruby-gradle-plugin