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)
Also got rid of the MAVEN_BUILD_LOCAL flag. Here's the build.properties you'll need which is really the same as the old one.

systemProp.MAVEN_UPLOAD_REPO_URL=System.getProperty('user.home'), '.m2/repository'
systemProp.MAVEN_UPLOAD_VERSION=1.0.0-beta3rc1
systemProp.MAVEN_UPLOAD_USERNAME='user'
systemProp.MAVEN_UPLOAD_PASSWORD='[*]'