Add @api stable annotations for ol.coordinate
Mark map.beforeRender as unstable
Only document olx properties marked as part of the API

And mark all olx properties with @api.  The stability level will be used to determine what can change between minor releases.
Document stability for options
Merge pull request #2589 from tschaub/olx-property-stability

Document stability for olx properties
Add @api stable annotations for ol.source.BingMaps
Add a reference to the license to the build
Add @api stable annotations for ol.source.ImageStatic
Add @api stable annotations for ol.source.ImageWMS
Add @api stable annotations for ol.source.MapQuest
Add @api stable annotations for ol.source.OSM
Add @api stable annotations for ol.source.Source
Add @api stable annotations for ol.source.Stamen
Add @api stable annotations for ol.source.TileJSON
Add @api stable annotations for ol.source.Tile
Add @api stable annotations for ol.source.TileWMS
Add @api stable annotations for ol.source.Vector
Add @api stable annotations for ol.source.WMTS
Remove ol.source.WMTS.optionsFromCapabilities from the API
Add @api stable annotations for ol.source.XYZ