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/include/Makefile.am b/include/Makefile.am
index aa735c5..2a99211 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -5,4 +5,5 @@
  osmocom/abis/subchan_demux.h osmocom/abis/e1_input.h			\
  osmocom/abis/lapd.h osmocom/abis/lapd_pcap.h osmocom/trau/osmo_ortp.h	\
  osmocom/abis/unixsocket_proto.h \
- osmocom/trau/trau_frame.h
+ osmocom/trau/trau_frame.h \
+ osmocom/trau/trau_sync.h