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/source/tilewmssource.js

@@ -23,7 +23,6 @@ goog.require('ol.source.wms.ServerType');
  * @constructor
  * @extends {ol.source.TileImage}
  * @param {olx.source.TileWMSOptions=} opt_options Tile WMS options.
- * @todo stability experimental
  * @todo api
  */
 ol.source.TileWMS = function(opt_options) {
@@ -125,7 +124,6 @@ goog.inherits(ol.source.TileWMS, ol.source.TileImage);
  *     in the `LAYERS` parameter will be used. `VERSION` should not be
  *     specified here.
  * @return {string|undefined} GetFeatureInfo URL.
- * @todo stability experimental
  * @todo api
  */
 ol.source.TileWMS.prototype.getGetFeatureInfoUrl =
@@ -208,7 +206,6 @@ ol.source.TileWMS.prototype.getKeyZXY = function(z, x, y) {
  * Get the user-provided params, i.e. those passed to the constructor through
  * the "params" option, and possibly updated using the updateParams method.
  * @return {Object} Params.
- * @todo stability experimental
  * @todo api
  */
 ol.source.TileWMS.prototype.getParams = function() {
@@ -309,7 +306,6 @@ ol.source.TileWMS.prototype.getTilePixelSize =
 /**
  * Return the URLs used for this WMS source.
  * @return {Array.<string>|undefined} URLs.
- * @todo stability experimental
  * @todo api
  */
 ol.source.TileWMS.prototype.getUrls = function() {
@@ -394,7 +390,6 @@ ol.source.TileWMS.prototype.tileUrlFunction_ =
 /**
  * Update the user-provided params.
  * @param {Object} params Params.
- * @todo stability experimental
  * @todo api
  */
 ol.source.TileWMS.prototype.updateParams = function(params) {