Accept port range

Accept a range of ports to listen to, so that it does not fail if
another instance of scrcpy is currently starting.

The range can be passed via the command line:

    scrcpy -p 27183:27186
    scrcpy -p 27183  # implicitly 27183:27183, as before

The default is 27183:27199.

Closes #951 <https://github.com/Genymobile/scrcpy/issues/951>