trau-decode: refactor trau-hr-dump The desire is to create a companion program that will read hex lines representing TRAU-8k frames and then decode those frames in exactly the same way how we currently decode frames read from binary capture files. Hence the decoder portion of trau-hr-dump needs to be factored out.

The two starting source files in this directory (e1_ts2_efr.bin and
e1_ts2_fr.bin) originate from Osmocom:

https://cgit.osmocom.org/libosmo-abis/tree/contrib/trau2rtp

The Makefile contained here automates the process of extracting interesting
bits from these E1 Abis UL recordings.