Currently the animation functions share the same module, namely ol.animation. We do differently for ol.control.defaults and ol.interaction.defaults, with ol.control.defaults and ol.interaction.defaults module. This commit replaces the ol.animation module by four modules, one for each animation function.
This makes things more consistent, and will make it possible to use the @exportFunction annotation for the exporting of the animation functions.
Adding a new DragBox control and using it in the shiftdragzoom interaction to provide visual feedback of the zoom box. The control is nicely separated from the interaction - it only draws the box and does not perform any action.