Track Rust master
Track Rust master
Merge pull request #39 from mikedilger/minorfixes

Track Rust master
Add shorthands for creating listening sockets

These a of particular use when you e.g. receive socket address to listen from
downstream code or from configuration file. They also make UDP and TCP API look
a bit more similar to what stdlib provides and reduce typing for very common
cases. 3 methods added:
- SockAddr.family() get AddressFamily of the address
- UdpSocket::bound() create listening UDP socket similar to stdlib
  UdpSocket::bind()
- TcpAcceptor::new() create listening TCP socket hiding intermediate steps
Add methods for converting between stdlib and ad-hoc SockAddr

As mio is concerned with few memory allocations, two versions of each function
are provided: consuming (no clone()) and using reference (with clone()).
Use Vec []-operator instead of deprecated get_mut