tizaudioport: added tiz_port_set_portdef_format override.
mp3_decoder: fixed port disable/enable sequences (buffers should not be processed/leave the component when ports are disabled).
buildtizonia: added Mp3StreamingClientPortAutoDetect to list of exempt skema tests.
http_source: more fixes (Mp3StreamingClient and Mp3StreamingClientPortAutoDetect skema suites now pass)
tizonia.conf.in: added HTTP source's default uri