Use equality semantics for compiler tests

Closes #776.

Thanks, @radix!
Merge pull request #786 from rackerlabs/transparent-retry-policies

Represent retry logic as transparent, easily testable policy objects
Merge pull request #788 from rackerlabs/conv-request-tests-cleanup

Use equality semantics for compiler tests
Merge branch 'master' into pure-server-info-2

Conflicts:
	otter/test/test_convergence.py