Bugfix release

Fixed bugs:
-fix compilation on 32bit systems
-fix regression in stats obj rtt value
-remove unneeded locking in buffer scaling
-fix too old packages error due to buffer scaling
-fix empty buffer time check
-disable buffer negotiation when sender max buffer is smaller than our buffer
-fix deadlock caused by wrong lock order when removing peers
-fix building Prometheus code against older libmicrohttpd
-fix compilation on Hurd

Multiplexing and TUN support

First official public release