Connection handling redesign (yet compatible to original)

Add per peer queueing of connection commands
Add send window for reliable packets
Removed send window adjustment by rtt
Imediately send acks
Cleanup reliable packet queuing (now queue directly to peers)
Add per channel congestion window handling by lost packets
Fix sequence number handling and add checking
Improved rtt/timeout calculation
Added fix for sequence number overrun
Add packets per iteration counter check
Add some profiling
Add support for cleaning up unused profilers
Add debug feature to show per peer bandwidth statistics each 20 seconds
Add buggy legacy client workaround
Add setting to adjust workaround window size
Split networking to send/receive threads

Conflicts:
	src/connection.cpp
	src/server.cpp
	src/util/container.h