glretrace: Plug INTEL_perfquery to the collection.
glretrace: Plug INTEL_perfquery to the collection.

Add an entry in glretrace::getBackend().
Pass current context to INTEL_perfquery constructor, so that it can check if
corresponding GL extension is supported.

schulmar/apitrace,trtt/apitrace,apitrace/apitrace,EoD/apitrace,apitrace/apitrace,EoD/apitrace,schulmar/apitrace,trtt/apitrace,EoD/apitrace,schulmar/apitrace,apitrace/apitrace,EoD/apitrace,apitrace/apitrace,schulmar/apitrace,schulmar/apitrace,trtt/apitrace,trtt/apitrace,trtt/apitrace,EoD/apitrace