$timeout.cancel happily accepts null/undefined promises.  Update the externs jsdoc to match the upstream source.
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=75731088
Remove a couple of duplicate definitions in externs.

(Even though these are vendor-prefixed versions,
they are defined alongside the standard visibilityState
in html5.js)
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=75733932
Add bindToController property of the Angular directive definition object.
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=75743703
Remove @override annotation on non-methods in externs
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=75750564
Make Node.prototype.baseURI nullable as per spec
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=75753079