Add geom.Collection & geom.collection.

Also make MultiPoint and multipoint inherit from Collection/collection
respectively.

src/ol/geom/Collection.js

@@ -0,0 +1,61 @@
+goog.provide('ol.geom.Collection');
+
+goog.require('goog.array');
+goog.require('ol.geom.Geometry');
+goog.require('ol.Projection');
+
+/**
+ * Creates ol.geom.Collection objects. 
+ * 
+ * @extends {ol.geom.Geometry}
+ * @param {Array.<ol.geom.Geometry>} components An array of components.
+ * 
+ * @constructor
+ */
+ol.geom.Collection = function(components) {
+    /**
+     * @private
+     * @type {Array.<ol.geom.Geometry>}
+     */
+    this.components_ = components;
+    
+};
+
+goog.inherits(ol.geom.Collection, ol.geom.Geometry);
+
+/**
+ * Sets the Collection's components.
+ * 
+ * @return {Array.<ol.geom.Geometry>} An array of components.
+ */
+ol.geom.Collection.prototype.getComponents = function() {
+    return this.components_;
+};
+
+/**
+ * Gets the Collection's components.
+ * 
+ * @param {Array.<ol.geom.Geometry>} components An array of components.
+ */
+ol.geom.Collection.prototype.setComponents = function(components) {
+    this.components_ = components;
+};
+
+/**
+ * Adds the given component to the list of components at the specified index.
+ * 
+ * @param {ol.geom.Geometry} component A component to be added.
+ * @param {number} index The index where to add.
+ */
+ol.geom.Collection.prototype.addComponent = function(component, index) {
+    goog.array.insertAt(this.components_,component,index);
+};
+
+/**
+ * Removes the given component from the list of components.
+ * 
+ * @param {ol.geom.Geometry} component A component to be removed.
+ */
+ol.geom.Collection.prototype.removeComponent = function(component) {
+    goog.array.remove(this.components_, component);
+};