Only pan the map when the mouse action button is pressed
Taking advantage of GitHub's rendering of .geojson
Merge pull request #796 from tschaub/geojson-rename

Use .geojson extension for GeoJSON
Merge pull request #795 from fredj/pan_actionbutton

Right click pan
Add layergroup support
Add layergroup exports
Add tests for ol.layer.LayerGroup
Add tests for layer.getLayerState()
Add a layer-group example
Get opacity from layerState in webglmaprenderer

instead of getting it from layer.getOpacity().
Fix the issue of changing opacity which didn't work with LayerGroups in webgl.
Bind more layer properties in layer-group example

This allow to update hue, saturation, brightness, contrast values.