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/geom/linestring.js

@@ -20,7 +20,6 @@ goog.require('ol.geom.flat.simplify');
  * @extends {ol.geom.SimpleGeometry}
  * @param {ol.geom.RawLineString} coordinates Coordinates.
  * @param {ol.geom.GeometryLayout|string=} opt_layout Layout.
- * @todo stability experimental
  * @todo api
  */
 ol.geom.LineString = function(coordinates, opt_layout) {
@@ -60,7 +59,6 @@ goog.inherits(ol.geom.LineString, ol.geom.SimpleGeometry);
 
 /**
  * @param {ol.Coordinate} coordinate Coordinate.
- * @todo stability experimental
  * @todo api
  */
 ol.geom.LineString.prototype.appendCoordinate = function(coordinate) {
@@ -117,7 +115,6 @@ ol.geom.LineString.prototype.closestPointXY =
  * @param {number} m M.
  * @param {boolean=} opt_extrapolate Extrapolate.
  * @return {ol.Coordinate} Coordinate.
- * @todo stability experimental
  * @todo api
  */
 ol.geom.LineString.prototype.getCoordinateAtM = function(m, opt_extrapolate) {
@@ -133,7 +130,6 @@ ol.geom.LineString.prototype.getCoordinateAtM = function(m, opt_extrapolate) {
 
 /**
  * @return {ol.geom.RawLineString} Coordinates.
- * @todo stability experimental
  * @todo api
  */
 ol.geom.LineString.prototype.getCoordinates = function() {
@@ -144,7 +140,6 @@ ol.geom.LineString.prototype.getCoordinates = function() {
 
 /**
  * @return {number} Length.
- * @todo stability experimental
  * @todo api
  */
 ol.geom.LineString.prototype.getLength = function() {
@@ -195,7 +190,6 @@ ol.geom.LineString.prototype.getType = function() {
 /**
  * @param {ol.geom.RawLineString} coordinates Coordinates.
  * @param {ol.geom.GeometryLayout=} opt_layout Layout.
- * @todo stability experimental
  * @todo api
  */
 ol.geom.LineString.prototype.setCoordinates =