Small clean ups in EntityParserOutputGenerator related code

* Add missing and fix wrong PHPDoc tags.
* Optimize use clauses.
* Use switch for code that looks like a switch.
* Rename $revId to $revisionId.

Change-Id: I3bc3a356c63c33bc82cf960b27eab77e1f86a03a
Merge "Small clean ups in EntityParserOutputGenerator related code"