* [NOD-142] Updated util.FastLog2Floor to work on uint64
* [NOD-142] Convert height and chainHeight to uint64
* [NOD-142] A couple fixes in comments of TestFastLog2Floor
* [NOD-142] Make spendableOutOffset uint64 too
* [NOD-122] Handle each message in rpcclient with a separate goroutine
* [NOD-122] Stop listening to new blocks when not mining
* [NOD-122] Made RPC logging in mining simulator more explicit + some styling enhencement