Have an experiment in pronghorn that breaks when you have partner
calls and endpoint calls.  This infrastructure will help test the
combination of the two.
Added a unit test that hangs when making combinations of endpoint and partner calls.
Added names that each endpoint prints when it returns to simplify debugging.
When transitioned from model where each individual endpoint on a host
has its own separate event that, in aggregate, add up to form full
event, to each host has a single representation for an event, we
forgot to send back commit messages on behalf of local endpoints: if
one event commits on an endpoint on a host, the event will commit for
every endpoint on the host.  Note that we should batch the endpoint
updates instead of sending them back as serial messages.
Removed some debugging print statements from one of the tests.