remove obsolete schemas and functions

* Remove schema.OpenTask and schema.CommunityPortal (openTask only logs
events from GettingStarted).
* Remove window._evq.track function in ext.Experiments.eventlog module
that MobileFrontend copied in December.
* Remove unused mw.e3.track and mw.e3.murmur3 functions.
* Remove obsolete CommunityPortal functions from openTask handling.

Clients stopped using these in early January 2013.

Change-Id: Idbc6bb408c3b7c4cc28c2e8a52a3ce0f77e773f7