Cache array length in ol.control.Attribution
Remove ol.tilegrid.TileGrid#getPixelBoundsForTileCoordAndResolution
Remove ol.PixelBounds
Merge pull request #636 from twpayne/cache-length

Cache array length in ol.control.Attribution
Merge pull request #637 from twpayne/remove-unused-functions

Remove unused functions
Redefine ol.Pixel to be Array.<number>