* Add tests for device list updates
* Add stale_device_lists table and use db before asking remote for device keys
* Fetch remote keys if all devices are requested
* Add display_name col to store remote device names
Few other tweaks to make `Server correctly handles incoming m.device_list_update`
pass.
* Fix sqlite otk bug
* Unbuffered channel to block /send causing sytest to not race anymore
* Linting and fix bug whereby we didn't send updated dl tokens to the client causing a tightloop on /sync sometimes
* No longer assert staleness as Update blocks on workers now
* Back out tweaks
* Bugfixes
* Add storage layer for postgres/sqlite
* Return OTK counts when inserting new keys
* Hook up the key DB and make a test pass
* Convert postgres queries to be sqlite queries
* Blacklist test due to requiring rejected events
* Unbreak tests
* Update blacklist
Kegsay
Neil Alexander