tests/icles/: Small oss4 test that probes for available devices and retrieves their caps and mixer tracks and all tha...

Original commit message from CVS:
* tests/icles/.cvsignore:
* tests/icles/Makefile.am:
* tests/icles/test-oss4.c: (opt_show_mixer_messages), (WAIT_TIME),
(show_mixer_messages), (probe_mixer_tracks), (probe_pad),
(probe_details), (probe_element), (main):
Small oss4 test that probes for available devices and retrieves
their caps and mixer tracks and all that. Also allows testing of
mixer change messages on the bus.