Let's add a VTY interface on TCP port 4269. The purpose is - for now -
not for configuration storage, but for state introspection.
Change-Id: I47b6e4efaad52e68e2b50a7993076f3706f86628
libosmousb, recently introduced to libosmocore.git, is taking care
of main loop integration of libusb into osmo_select_main(). This
means we don't need to do any polling here anymore.
Change-Id: I3f3b61dfa217d6ef8c17970b2cf1cc627bb13bbe