Add support for "q921_all"/"q931_all" to parse_debug() ("debug" span parameter), taken from
ftmod_libpri.

Passive libpri's raw dump feature is broken (e.g. I-frames missing), so
add "q921_raw" hexdump support to the pritap I/O read/write function.
Signed-off-by: Stefan Knoblich <stkn@openisdn.net>