Gradle system properties

Potential way of both building against snapshots versus releases with teamcity as well as building projects that require external libraries with teamcity. 


Consistency mostly. I figure we'd offer the users home directory as a default for the libs (to make TeamCity builds easier), and they can always change it when they checkout. I don't think this is the perfect change, but it seems doable. 

I suppose we could add a build flag in the build.gradle that TeamCity can have defined to find the libs elsewhere, but that also clogs up the build.gradle.