First sketch of MBTiles export UI. Refs #43.
Clear timeout when cancelling.
Add bounds autodetection to export. Better logging. Refs #43.
Merge branch 'master' into source-mbtiles
Fix relative paths for datasource handling.
Emit started event for tests to hook into.
Add tests for creating copytasks, clearing copytasks.
Merge branch 'master' into source-mbtiles