Implement a user client without dependencies on git and Ruby

[cornelius]

The current command line client requires Ruby to run and makes use of git to get the library meta data. This is not a problem when packaged properly or when run on a Linux system which has developer tools set up, but it can cause trouble in the general case. One way to mitigate this would be to implement a client which doesn't have these dependencies. One option would for example be to fully implement it in Go. This would result in executables which can easily be distributed and run.