* Rough first pass at adding room version abstractions
* Define newer room versions
* Update room version metadata
* Fix roomserver/versions
* Try to fix whitespace in roomsSchema
* Merge forward
* Tidy up a bit
* TODO: What to do with NextBatch here?
* Replace SyncPosition with PaginationToken throughout syncapi
* Fix PaginationTokens
* Fix lint errors
* Add a couple of missing functions into the syncapi external storage interface
* Some updates based on review comments from @babolivier
* Some updates based on review comments from @babolivier
* argh whitespacing
* Fix opentracing span
* Remove dead code
* Don't overshadow err (fix lint issue)
* Handle extremities after inserting event into topology
* Try insert event topology as ON CONFLICT DO NOTHING
* Prevent OOB error in addRoomDeltaToResponse
* Thwarted by gocyclo again
* Fix NewPaginationTokenFromString, define unit test for it
* Update pagination token test
* Update sytest-whitelist
* Hopefully fix some of the sync batch tokens
* Remove extraneous sync position func
* Revert to topology tokens in addRoomDeltaToResponse etc
* Fix typo
* Remove prevPDUPos as dead now that backwardTopologyPos is used instead
* Fix selectEventsWithEventIDsSQL
* Update sytest-blacklist
* Update sytest-whitelist
