Instead of having `ol.events.Key` be a listener object or an array of listener objects, it should be less error prone to have it just be a single listener object.
To avoid using too many functions with multiple return types, the `ol.events.*` functions for registering and unregistering listeners no longer accept an array of event types (and only a single key is returned when registering).
To make it convenient for users to register multiple listeners at once, the `observable.on()` method accepts an array of event types. Internally in the library, we should use the less risky `ol.events.listen()`.
With this change map.setView(null) is permitted, but map.setView(undefined) is not. map.getView now always returns a defined value, which may be null is setView was called with null.
The change in #2098 made it so a feature's geometry could be undefined. This is consistent with the return type for the getGeometry method. Where calling code needs to ensure that it has a geometry instance, it can use instanceof, goog.isDefAndNotNull(), or test for a truthy value.
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.
This commit simplifies the exports.js plugin so it only relies
on the stability notes to generate the documentation, which
completely decouples it from the exportable API.
As a rule of thumb, whenever something has an 'api' annotation,
it should also have a 'stability' annotation. A more verbose
documentation of ol3 specific annotation usage is available in
the new 'apidoc/readme.md' file.
This commit also modifies all source files to implement these
usage suggestions.
