Added WaitFor event stack polling method to give us the ability to
both have a tighter (faster) test run, but also assert within a
more globally defined time frame, which events should be seen
within a time bound.
Additionally, an open field was introduced to prevent exceptions
when the websocket is not open.
Added hangup method, and a 401 exception.
SIP agents now implicitly hangup all their calls when asked to quit.
Removed potential race condition that caused tests to fail.
Now, every tests will try to use a new agent.
Added initialization to apparently static fields.
Added HangupAllCalls method.
Made the call list class iterable from outside.
Fixes to tests.
Merge branch 'master' of github.com:AdaHeads/Coverage_Tests

Conflicts:
	src/call_tests.py