Add ol.View2D#getZoom
Export ol.View2D#getZoom
Merge pull request #858 from elemoine/getzoom

Add ol.View2D#getZoom
Export TileGrid functions
Export tilegrid.WMTS functions
Export ol.source.TileSource and its getTileGrid func
Export ol.layer.Layer and its getSource func
Getters and setters for line symbolizers
Preserve unexpected items in options object passed to the constructor
Getters and setters for polygon symbolizer
Getters and setters for shape symbolizers
Fixing bug with IconLiteral#equals and adding tests
Getters and setters for icon symbolizer
Adding tests for text symbolizer
Getters and setters for text symbolizer
Merge pull request #861 from fredj/layer-options

Preserve unexpected items in options object passed to the constructor
Merge pull request #862 from tschaub/mutable-symbolizers

Provide getters and setters for symbolizer properties
Initialize all the items in tileRangeByZ
Add zoom to extent control
Add navigation controls example