OsmoMGW: document the 'X-Osmo-IGN' MGCP extension

See also Ia6fe5ead4b601931c1bf41b29fc1b237aac37d2c in osmo-mgw.git, which
changes the initial single-character implementation to match this specification
of string tokens separated by spaces.

Change-Id: If15a88c3b5b40fd1d24ad0f94f3231f678669ab1
2 files changed
tree: 0a92857adf20c41c3a3a0d45aa9c53a2f3e6e5e2
  1. doc/