Change copyright from me to Ambient Entertainment

The work I have done for pyfarm and the documentation has been done in a
work-for-hire context for Ambient Entertainment GmbH & Co. KG.  As such,
the copyright does not lie with me in person, but rather with my
employer, Ambient Entertainment.

The license is still Apache License 2.0.
Merge pull request #5 from guidow/ambient_copyright

Change copyright from me to Ambient Entertainment