Java Buildpack 2.2

This change updates the Java Buildpack to version 2.2.  Version
2.2 has the following highlights:

* Credentials in repository URIs (via Shaozhen Ding)
* Groovy 2.3 support
* Auto-reconfiguration support for Servlet 3 and distZip style
  applications
* Buildpack packaging on Windows (via kjhawar)

Both the online and offline buildpacks are updated as part of this
change.