* Storage functions for invite events
* Add table for tracking membership state
* More stuff
* More stuff
* Use utility methods from gomatrixserverlib, rather than reimplementing them
* More stuff
* Return string rather than pointer to string
* Update gomatrixserverlib
* Use HTTP API for roomserver input.
* Use synchronous HTTP API for writing events to the roomserver
* Remove unused config for kafka topic
* Add new output types to roomserver for invites
* Write membership updates
* Separate filtering from pairing up changes in membershipChanges
* Fix SQL
* Fix SQL
* Namespace the tables
* Fix SQL
* Use clearer names for some of the variables
* Rename senderID for consistency
* Restructure update membership
* Comments
* More comment
* Fix SQL
* More comments
* Assign state keys inside the transaction
* Comment on the purpose of the latestEventsUpdater
* Comment on the purpose of updateMembership
* Remove duplicate fields from stateChange
* Attempt to rewrite comment in 'english'
* More comments
* Fix comment
* Comment
* more comments
