Several fixes and improvements to the documentation.
This documentation still doesn't contain infrmation about TRXDv1, it
will be added in a follow-up commit.
Change-Id: I36e6206b90435964842f9f1ebd982cdaf9777018
This chapter defines the protocol used between osmo-trx and
osmo-bts-trx.
Most of the text comes originally from osmo-trx.git/README, as it's the
only known documentation of the protocol other than the code itself.
Change-Id: I56c418eef0f826ae1aadbed5b151fbed241c7885
Pau Espin