Assert no messages when quiescent

Change peek scheduler to assert that no messages are sent when the system is supposed to be
quiescent
Merge commit '0b9f19cf19473fa69e80aa586338d9409d869a40' into colin-rbcast

Conflicts:
	interposition/src/main/scala/verification/schedulers/PeekScheduler.scala
Merge pull request #16 from apanda/master

Additional assertions in Peek Scheduler
DPOR.
Get build to work
Merge commit '188780fbcbb6fa96dea94f89bbbcecd46c01d041' into colin-rbcast
Fix build to support DPOR