The logic for marking invites as locally rejected was all well and good, but
didn't happen when the remote server returned a 500, or wasn't reachable, or
had no DNS, or whatever.

Just expand the except clause to catch everything.

Fixes https://github.com/matrix-org/synapse/issues/761.

inline `reject_remote_invite`, which only existed to make tracing the callflow
more difficult.

The documentation on get_json has been wrong ever since the very first commit
to synapse...

Also:
 - change the REST endpoint to have a "S" on the end (so it's now /read_markers)
 - change the content of the m.read_up_to event to have the key "event_id" instead of "marker".

Update README.rst

The FreeBSD port has been moved to the net-im category

Implement Read Marker API

Reduce federation replication traffic

Add a counter metric for successfully-sent transactions

Dedupe KeyedEdu and Devices federation repl traffic

Remove HTTP replication APIs

Fix getting latest device IP for user with no devices