Fixes build script to work without fetching artifacts from the rosjava repo.
Fixes a bugs associated with adding repositories from environment variables.
Updates Gradle wrapper version.
Fix message dependency computation.
Removes RosJavaPlugin in favor of having just the RosPlugin.
Fixes several bugs related to reading paths form environment variables.
Merge pull request #17 from damonkohler/work

Lots of bug fixes and clean ups.