Beta 0.1.6

• The installation script now works on systems where python2 still is the default
• Patched some problems with how the server object handled new server jars (you can no longer set server.version = new_version directly). You will now update them using server.update(new_version)
• Now sends SIGINT because SIGTERM caused a forking tmux instance to forcefully quit instead of stopping the server first.