Store stdev of rtt in the TCB cache as per RFC 2140
Implement RTT update on first ack
propagate from branch 'i2p.i2p' (head e301d0499f4c688ed3a5febe30bf8098c7f2cdf9)
            to branch 'i2p.i2p.979' (head 2dfdeb022c9495461b2ec1d90f28ef9cd0bd9e22)
better loading from cache
sync getters
Hardcode TCP constants
	Various suggestions by zzz
compute rttDev in updateRTT
Prepare for merge