Add ability to send arbitrary UNIX signals to processes:
* Extend the Process class to handle non-killing signals
* Expose this via the XML-RPC API
Fix Python 3 incompatibilities
Remove extra whitespace
Sort results for deterministic results

despite hash randomization
Add frontend (supervisorctl) support for signalling processes
Remove extra space around =

for consistency and PEP8
Replace _getSignalFromString with supervisor.datatypes.signal_number
sendProcessSignal: No need to return a callback

Work is already done by process.signal()
supervisor/rpcinterface.py: from supervisor.datatypes import
signal_number
Check for bad signal
Fix failing test: test_sendProcessSignal

and make sendProcessSignal return True
Merge branch 'Weebly_send_signals' of github.com:SurveyMonkey/supervisor into SurveyMonkey-Weebly_send_signals
as per comment attached to #477, rename sendXSignal to signalX, dont do anything async in signalGroup, merge logic for _stopresult and _signalresult in supervisorctl