Merge pull request #2525 from fredj/reuse-tileRange

Reuse tileRange in ol.renderer.Layer#manageTilePyramid
Fix incorrect maximum extent in xyz-retina example
Return rather than fail if resolution is not defined
Fix attribution in xyz-retina example
Fix ol.format.GML.readProjectionFromNode
Merge pull request #2526 from fredj/xyz-retina

Fix incorrect maximum extent in xyz-retina example
Added 'state' constructor option to Tile and TileImage sources
Added "state" property of olx.source.TileImageOptions to the olx externs
Remove unneeded ol.DebugTile_#tileCoord_ variable
Merge pull request #2531 from fredj/debugtile-cleanup

Remove unneeded ol.DebugTile_#tileCoord_ variable
Add ol.TileRange#containsXY function
Be stricter with types
Merge pull request #2529 from petrsloup/source-state-fix

Fix for invalid initial state of certain sources
Merge pull request #2532 from fredj/tilerange-cleanup

Add ol.TileRange#containsXY function
Enable ProjectionLike on getGetFeatureInfoUrl
Merge pull request #2348 from probins/getget

Enable ProjectionLike on getGetFeatureInfoUrl
Rename BrowserFeature to browserfeature
Merge pull request #2527 from pagameba/cluster-fix

Return rather than fail if resolution is not defined
Change ol.TileCoord to an Array
Merge pull request #2539 from elemoine/tilecoord

Change ol.TileCoord to Array.<number>