remove fmt parameter from ausrc/auplay api
ausrc/auplay api: change to 16-bit samples
update audio-driver modules with new ausrc/play API
re api changes:

- sip_param_decode() renamed to msg_param_decode()
- use msg_ctype_cmp() to check for Content-Type
stream_debug: also print local SDP address
dtmfio: fix warnings and improve detection
portaudio: fix clang warnings
ua: prefix contact-user cookie with SIP username
added call_setup_duration() and some small things

- Thanks to Lorenzo Mangani for this work
config: add opensles to template
sndio: audio driver for OpenBSD

It was contributed by Dmitrij D. Czarkoff, thank you!
debian: baresip now needs libre v0.4.8 or later
sndio: update to new ausrc/auplay API
dtmfio: include unistd for unlink()
selftest: new module for testing baresip core

the selftest module is using the public API of the
Baresip core (in baresip.h) to verify the expected
behaviour and to test various protocol scenarios.

the module can be loaded with the 'module' directive
or 'module_tmp' directive:

    module_tmp        selftest.so

OR:

    module            selftest.so
play: fix warnings when compiling with OPT_SIZE=1
use logging functions
added some missing comments
modules: use new logging functions
metric: fix average bitrate calculation