Handle params == null (e.g. getblockcount)
Handle case where reservedByAccept is null
Implement blockHeight in Consensus checks

* Re-fetch Master Core consensus if block height changed
* Get Omni block height and also refetch if necessary
* Check block height and report differences in tests

Note: We are not ensuring that block height matches between Omni
and Master Core (this would require waiting too long, I think)