Version 1.7.0

• Fixed regression introduced during refactoring (write_buffer(x, x) could generate invalid results or potentially segfault)
• Changed socket binding behaviour. You will now get an error if a port is already in use.
• Added functions tcp_listening_v4(acceptor) and tcp_listening_v6(acceptor) which can be used to find out if an acceptor is listening for IPv4/IPv6 connections, in case only one of these is working.