Get rid of stability annotations and document stability with api

This change adds a stability value to the api annotation, with
'experimental' as default value.

enum, typedef and event annotations are never exportable, but
api annotations are needed there to make them appear in the
docs.

Nested typedefs are no longer inlined recursively, because the
resulting tables get too wide with the current template.

src/ol/collection.js

@@ -19,13 +19,13 @@ ol.CollectionEventType = {
   /**
    * Triggered when an item is added to the collection.
    * @event ol.CollectionEvent#add
-   * @todo stability experimental
+   * @todo api
    */
   ADD: 'add',
   /**
    * Triggered when an item is removed from the collection.
    * @event ol.CollectionEvent#remove
-   * @todo stability experimental
+   * @todo api
    */
   REMOVE: 'remove'
 };
@@ -47,7 +47,6 @@ ol.CollectionEvent = function(type, opt_element, opt_target) {
   /**
    * The element that is added to or removed from the collection.
    * @type {*}
-   * @todo stability experimental
    */
   this.element = opt_element;
 
@@ -70,7 +69,6 @@ ol.CollectionProperty = {
  * @extends {ol.Object}
  * @fires {@link ol.CollectionEvent} ol.CollectionEvent
  * @param {Array=} opt_array Array.
- * @todo stability experimental
  * @todo observable length {number} readonly the length of the array
  * @todo api
  */
@@ -92,7 +90,6 @@ goog.inherits(ol.Collection, ol.Object);
 
 /**
  * Remove all elements from the collection.
- * @todo stability experimental
  * @todo api
  */
 ol.Collection.prototype.clear = function() {
@@ -105,7 +102,6 @@ ol.Collection.prototype.clear = function() {
 /**
  * @param {Array} arr Array.
  * @return {ol.Collection} This collection.
- * @todo stability experimental
  * @todo api
  */
 ol.Collection.prototype.extend = function(arr) {
@@ -124,7 +120,6 @@ ol.Collection.prototype.extend = function(arr) {
  *     index and the array). The return value is ignored.
  * @param {S=} opt_this The object to use as `this` in `f`.
  * @template T,S
- * @todo stability experimental
  * @todo api
  */
 ol.Collection.prototype.forEach = function(f, opt_this) {
@@ -138,7 +133,6 @@ ol.Collection.prototype.forEach = function(f, opt_this) {
  * collection's "length" property won't be in sync with the actual length
  * of the array.
  * @return {Array} Array.
- * @todo stability experimental
  * @todo api
  */
 ol.Collection.prototype.getArray = function() {
@@ -150,7 +144,6 @@ ol.Collection.prototype.getArray = function() {
  * Get the element at the provided index.
  * @param {number} index Index.
  * @return {*} Element.
- * @todo stability experimental
  * @todo api
  */
 ol.Collection.prototype.getAt = function(index) {
@@ -161,7 +154,6 @@ ol.Collection.prototype.getAt = function(index) {
 /**
  * Get the length of this collection.
  * @return {number} Length.
- * @todo stability experimental
  * @todo api
  */
 ol.Collection.prototype.getLength = function() {
@@ -173,7 +165,6 @@ ol.Collection.prototype.getLength = function() {
  * Insert an element at the provided index.
  * @param {number} index Index.
  * @param {*} elem Element.
- * @todo stability experimental
  * @todo api
  */
 ol.Collection.prototype.insertAt = function(index, elem) {
@@ -187,7 +178,6 @@ ol.Collection.prototype.insertAt = function(index, elem) {
 /**
  * Remove the last element of the collection.
  * @return {*} Element.
- * @todo stability experimental
  * @todo api
  */
 ol.Collection.prototype.pop = function() {
@@ -199,7 +189,6 @@ ol.Collection.prototype.pop = function() {
  * Insert the provided element at the end of the collection.
  * @param {*} elem Element.
  * @return {number} Length.
- * @todo stability experimental
  * @todo api
  */
 ol.Collection.prototype.push = function(elem) {
@@ -213,7 +202,6 @@ ol.Collection.prototype.push = function(elem) {
  * Removes the first occurence of elem from the collection.
  * @param {*} elem Element.
  * @return {*} The removed element or undefined if elem was not found.
- * @todo stability experimental
  * @todo api
  */
 ol.Collection.prototype.remove = function(elem) {
@@ -232,7 +220,6 @@ ol.Collection.prototype.remove = function(elem) {
  * Remove the element at the provided index.
  * @param {number} index Index.
  * @return {*} Value.
- * @todo stability experimental
  * @todo api
  */
 ol.Collection.prototype.removeAt = function(index) {
@@ -249,7 +236,6 @@ ol.Collection.prototype.removeAt = function(index) {
  * Set the element at the provided index.
  * @param {number} index Index.
  * @param {*} elem Element.
- * @todo stability experimental
  * @todo api
  */
 ol.Collection.prototype.setAt = function(index, elem) {