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/render/renderevent.js

@@ -11,17 +11,17 @@ goog.require('ol.render.IVectorContext');
 ol.render.EventType = {
   /**
    * @event ol.render.Event#postcompose
-   * @todo stability experimental
+   * @todo api
    */
   POSTCOMPOSE: 'postcompose',
   /**
    * @event ol.render.Event#precompose
-   * @todo stability experimental
+   * @todo api
    */
   PRECOMPOSE: 'precompose',
   /**
    * @event ol.render.Event#render
-   * @todo stability experimental
+   * @todo api
    */
   RENDER: 'render'
 };
@@ -47,13 +47,11 @@ ol.render.Event = function(
 
   /**
    * @type {ol.render.IVectorContext|undefined}
-   * @todo stability experimental
    */
   this.vectorContext = opt_vectorContext;
 
   /**
    * @type {oli.FrameState|undefined}
-   * @todo stability experimental
    */
   this.frameState = opt_frameState;
 
@@ -61,7 +59,6 @@ ol.render.Event = function(
    * Canvas context. Only available when a Canvas renderer is used,
    * null otherwise.
    * @type {CanvasRenderingContext2D|null|undefined}
-   * @todo stability experimental
    */
   this.context = opt_context;
 
@@ -69,7 +66,6 @@ ol.render.Event = function(
    * WebGL context. Only available when a WebGL renderer is used, null
    * otherwise.
    * @type {ol.webgl.Context|null|undefined}
-   * @todo stability experimental
    */
   this.glContext = opt_glContext;