Bug fix Ping/Pong, refactoring of Node, Node.GetBlocks, PerformanceCounter
Merge commit 'bf34dd2bbfe0363a68cad47ddd4516d55dbfd6c9'

Conflicts:
	NBitcoin/NBitcoin.csproj
	NBitcoin/Protocol/NodeServer.cs
	NBitcoin/Protocol/Payloads/getDataPayload.cs