`click` events are fired only if the mouse action button is pressed. This prevents `click` events from being fired when the middle mouse button is used.
Also, without this commit, in Chrome with emulated touch events enabled, double-clicking the map doesn't zoom the map. This is because `ol.BrowserFeature.HAS_TOUCH` is `false` in that environment. The commit fixes it by testing `isMouseActionButton` on mouse devices only.
When we start dragging, we first handle dragstart and then set
the INTERACTING view hint and the dragging flag. To end dragging
in a symmetric manner, we have to first reset the INTERACTING
hint and dragging flag, and then handle dragend.
This flaw becomes obvious when using an interaction where no
animation is performed after the interaction. This can be seen
in the style-rules example when using the dragzoom interaction
(i.e. zoom using a drag box): the vector renderer will not
render the new resolution, because the INTERACTING view hint is
still set when the zoom box dragend is handled.
Refs #917. With the key hanler now attached to the map target by default we can remove the noModifierKeys condition for the keyboard zoom interaction. This will prevent the back button shortcut (alt + <back arrow>) to work, but it's ok, the map is focused so it's the one with the highest priority.
This follows the convention in the Closure Library of providing either namespace objects (where the property starts with a lowercase letter), constructors (where the property starts with an uppercase letter), or enums (all uppercase properties, only one instance of this in the closure library).
* Interaction is no goog.Disposable any more.
* Permanent cleanup during selection instead of disposeInternal.
* Moved selectionLayers creation outside feature loop.
* Maintain selectedFeatures and unselectedFeatures only for
layers that have a setRenderIntent method.
