Added ContractRetrieverFacts
Put ContractRetrieverFacts in its own module
Added SignalRCompressionFacts, it essentially tests the API

- Also changed the tests to use the isSet method instead of ok where it makes sense
Added UtilityFacts to test out the key portions of the SignalR compression utilities

- Did not test the BuildDecompressResult because it is tested in the receiveHandler functional tests
- Also did not test the getContracts method because its utilized throughout the other methods