Fix export for ol.Geolocation.SUPPORTED
Fix export for ol.DeviceOrientation.SUPPORTED
Use @exportSymbol for exporting ol.webgl.SUPPORTED

For consistency with the way we export ol.DeviceOrientation.SUPPORTED and ol.Geolocation.SUPPORTED.
Add ol.CenterConstraint
Add center constraint to ol.View2D
Constrain center in ol.interaction.Interaction.pan
Constrain center in ol.interaction.DragPan
Apply center constraint in custom projection examples
Constrain center in ol.interaction.TouchPan
Replace source ready flag with loading/ready/error enum
Merge pull request #1048 from twpayne/source-state-enum

Replace source ready flag with loading/ready/error enum
Import libtess.js
Apply fixjsstyle to libtess.js
Fix @author tags
Add missing @return tag
Add missing @param tag
Fix indentation in commment
Add goog.provides and goog.requires
Correct @param type
Include libtess.js in build