Add new TRAU frame sync code

This code is able to detect and sync against a variety of TRAU
frame sync patterns.  Focus is so far on those patterns present on
16k sub-slots, but 8k sub-slots are expected to be supported soon,
too.

A new codebase for this is required as the old OsmoNITB code had
conflated a 16k sub-slot multiplexer with TRAU frame synchronization,
so there was no way to separate those two parts and hence no way to
support 8k sub-slots.

Change-Id: Ia6fe6228b0b8b9a27999f37ce1115ed5558881ea
diff --git a/tests/trau_sync/trau_sync_test.ok b/tests/trau_sync/trau_sync_test.ok
new file mode 100644
index 0000000..2555913
--- /dev/null
+++ b/tests/trau_sync/trau_sync_test.ok
@@ -0,0 +1,9 @@
+
+==> test_body
+demux_bits_cb 'test': 00000000000000001000000000000000100000000000000010000000000000001000000000000000100000000000000010000000000000001000000000000000100000000000000010000000000000001000000000000000100000000000000010000000000000001000000000000000100000000000000010000000000000001000000000000000100000000000000010000000000000001000000000000000
+demux_bits_cb 'test': 00000000000000001000000000000000100000000000000010000000000000001000000000000000100000000000000010000000000000001000000000000000100000000000000010000000000000001000000000000000100000000000000010000000000000001000000000000000100000000000000010000000000000001000000000000000100000000000000010000000000000001000000000000000
+demux_bits_cb 'test': 11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111
+demux_bits_cb 'test': 00000000000000001000000000000000100000000000000010000000000000001000000000000000100000000000000010000000000000001000000000000000100000000000000010000000000000001000000000000000100000000000000010000000000000001000000000000000100000000000000010000000000000001000000000000000100000000000000010000000000000001000000000000000
+demux_bits_cb 'test': 11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111
+demux_bits_cb 'test': 11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111
+demux_bits_cb 'test':