Add more content for the API doc

Involves additions to (there will be subsequent pull requests for other
classes):
- ol.Attribution
- ol.Collection
- ol.Expression
- ol.Feature
- ol.Geolocation
- ol.Map
- ol.Object
- ol.Overlay
- ol.Projection
- ol.View2D
- ol.control.Attribution
- ol.control.Control
- ol.control.FullScreen
- ol.control.Logo
- ol.control.MousePosition
- ol.control.ScaleLine
- ol.control.Zoom
- ol.control.ZoomSlider
- ol.dom.Input
- ol.filter.Filter
- ol.filter.Geometry
- ol.filter.Logical

src/ol/control/attributioncontrol.js

@@ -18,6 +18,10 @@ goog.require('ol.source.Source');
 
 
 /**
+ * Create a new attribution control to show all the attributions associated
+ * with the layer sources in the map. A default map has this control included.
+ * By default it will show in the bottom right portion of the map, but it can
+ * be changed by using a css selector for .ol-attribution.
  * @constructor
  * @extends {ol.control.Control}
  * @param {ol.control.AttributionOptions=} opt_options Attribution options.