make NukeExternalControl work in terminal mode

[sebastianelsner]

starting nuke with -t and doing the standard import and execution of the server does not work in terminal mode. Hangs right after "Trying port xy"

[HughMacdonald]

Check the new stuff that I recently merged in from the guys at Luma...

You can now do something like this directly from non-Nuke python:

    with NukeCommandManager() as conn:
        nuke = conn.nuke
        b = nuke.createNode('Blur')
        print b.writeKnobs()

This will automatically launch Nuke in terminal mode while you talk to it, and then quit it when you're finished.