* This commit updates a couple of the syncapi SQL queries to return additional columns that are required/expected by rowsToStreamEvents in output_room_events_table.go.
It's not exactly clear to me yet what transaction_id and session_id do, but these being added n #367 results in state events breaking the /sync endpoint.
This is a temporary fix. We need to come up with a better solution.
* gomatrix to gomatrixserverlib on some weird line change
* Tweaks from @babolivier review comments
This PR adds a gomatrixserverlib.Filter parameter to functions handling the syncapi_current_room_state table. It does not implement any filtering logic inside the syncapi IncrementalSync/CompleteSync functions, just the APIs for future use.
Default filters are provided as placeholders in IncrementalSync/CompleteSync, so behaviour should be unchanged (except the default 20 event limit)
SQL table will be changed. You can upgrade an existing database using:
```
ALTER TABLE syncapi_current_room_state ADD COLUMN IF NOT EXISTS sender text;
UPDATE syncapi_current_room_state SET sender=(event_json::json->>'sender');
ALTER TABLE syncapi_current_room_state ALTER COLUMN sender SET NOT NULL;
ALTER TABLE syncapi_current_room_state ADD COLUMN IF NOT EXISTS contains_url bool;
UPDATE syncapi_current_room_state SET contains_url=(event_json::json->>'content')::json->>'url' IS NOT NULL;
ALTER TABLE syncapi_current_room_state ALTER COLUMN contains_url SET NOT NULL;
```
Note: This depends on #436 (and includes all its commits). I'm not sure if Github will remove the duplicated commits once #436 is merged.
