minor cleanup of slavePortnum config
adjust tests for cleanup
rename startCommands to remoteStartCommand
Merge branch 'p/rename-startCommands' of git://github.com/djmitche/buildbot into slave-proto
Merge branch 'slave-proto' into nine

Conflicts:
	master/buildbot/process/remotecommand.py
	master/buildbot/test/fake/fakeprotocol.py
	master/buildbot/test/unit/test_changes_pb.py
	master/buildbot/test/util/protocols.py

+autopep8
Fix calculation of PB port number when activting PBChangeSource

Fixes #2570.