libtizonia: tiz_port_set_portdef_format is unnecesarily overriden in the concrete audio ports.
libtizonia: tizport.c:port_depopulate asserts in Executing state when there are no buffers allocated (closes #83).
libtizonia: Port enable event should be received at the processor only after the port is fully populated (closes #84).
tplay: A few more fixes in the http client graph.