comms/libusbmuxd: Import libusbmuxd-2.1.1

This project is a client library to multiplex connections from and to iOS
devices alongside command-line utilities. It is primarily used by
applications which use the libimobiledevice library to communicate with
services running on iOS devices.

The library does not establish a direct connection with a device but
requires connecting to a socket provided by the usbmuxd daemon.

The usbmuxd daemon is running upon installing iTunes on Windows and Mac OS
X. The libimobiledevice project provides an open-source reimplementation of
the usbmuxd daemon to use on Linux or as an alternative to communicate with
iOS devices without the need to install iTunes.
