Slight cleanup to keep all VM operations in methods.
Dirty fix to bring the post-disconnect logic out of the afterDisconnect method, to avoid two calls on separate threads.
Cleaned up experimental fix, and mark slave as offline rather than disconnect it, to prevent a build from hijacking it.
Merge pull request #13 from hrabbouh/master

New fix for afterDisconnect running twice, and builds attempting to start on a disconnecting slave.