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.
The generate-symbols.js task runs JSDoc on source files. Because this takes a long time (13s) to run on the whole library, the resulting symbols file includes additional metadata to make it possible to do incremental symbol generation on subsequent runs. The 'path' and 'extends' metadata for a symbol are used to determine what needs to be regenerated.
There are cases where a private class may inherit an exportable member (e.g. ol.DebugTile_#getTileCoord comes from ol.Tile#getTileCoord). We want to avoid making these exportable.
This generates info for all symbols annotated with "@todo api" (when Plovr is replaced, this will become "@api"). Generated metadata is written to stdout. A separate process will handle the output.
