tfo/find-is-hdr: move here from freecalypso-reveng This little program was developed in freecalypso-reveng Hg repository in 2023-03, when we didn't have a separate repository for network-side reverse eng, but now that we do have separate repositories for FreeCalypso (mobile side) vs network side reverse eng, move TFO RE work to the proper place.

This repository contains tools and notes related to reverse engineering of
various components on the network side of GSM, as well as behavioral reverse
engineering of actual commercial GSM networks.