Allow configurable version numbers for binaries

* Use system properties to set version number, maven remote repo, maven credentials
* Remove gradle.properties as gradle prioritizes those system properties over those supplied over the command line (which is stupid)
Merge pull request #1 from jpoon/master

Allow configurable version numbers for binaries
Support install task

* move pom properties to global namespace
Merge pull request #2 from jpoon/master

Support install task