Add CaughtUp() function (needed by later commits)
Don't request blocks when block invs received unless it's the syncnode, or we've CaughtUp()
Better logging of ProcessMessages() progress
Show downloaded block size and time taken to download.
Replacement stalled block logic. Depending on the situation, it will either disconnect
the peer (as previous behaviour), or it will reselect a syncnode (e.g. when 500 blocks
have been received from the syncnode).
indentation
Rename MarkBlockAsReceived to MarkBlockAsRequested to reduce confusion.
Force selection of a new syncnode since the current syncnode is about to stop sending blocks.