CLC-3960 Remove redundant forced-cache-write
Default get_feed_as_json calls "get_feed(force_cache_write)".
CLC-3960 Remove obsolete MyMergedModel class
NOJIRA Remove unneeded instance_key override
The superclass sets @id equal to @uid for UserSpecificModels
CLC-3960 Fix contract check for Live Updates
The class is expected to implement "get_last_modified" (see FeedUpdateWhiteboard)
CLC-3960 Allow feed-specific approaches to cache warming
CLC-3921 Implementing full delete support plus full-stack integration test

Squashed commit of the following:

commit a21b6faf73b071e34e98b4dba9aafb4e4cbb7e5d
Author: Chris Tweney <chris@media.berkeley.edu>
Date:   Wed Jul 16 13:56:07 2014 -0700

    CLC-3921 Tests now pass in Postgres, and Calendar work tables show in ccadmin

commit 773fc888ca6be7dd301100eb456febb90d78487f
Author: Chris Tweney <chris@media.berkeley.edu>
Date:   Wed Jul 16 11:25:58 2014 -0700

    CLC-3921 Put calendar spec back in testext

commit 9d3b69b7f87d456cb9e54b988d329450f89f34b1
Author: Chris Tweney <chris@media.berkeley.edu>
Date:   Wed Jul 16 11:22:59 2014 -0700

    CLC-3921 Make calendar spec pass in a postgres db environment

commit 4cb2080aa59b32c6674c5a4d90890ff124435b22
Author: Chris Tweney <chris@media.berkeley.edu>
Date:   Wed Jul 16 10:58:49 2014 -0700

    CLC-3921 Add a full-stack calendar integration test, and tweak log levels

commit c43ec62724d1c271a410cf6bac7164621f140513
Author: Chris Tweney <chris@media.berkeley.edu>
Date:   Tue Jul 15 16:17:23 2014 -0700

    CLC-3921 Make exporter delete events marked as delete transactions

commit 2854f5f356e922f2440c3fdcf16b9c3ea17bc595
Author: Chris Tweney <chris@media.berkeley.edu>
Date:   Tue Jul 15 15:21:31 2014 -0700

    CLC-3921 Record the type of transaction (create, update, delete) with entry logs

commit 33ceb487f777e03d209d758eec51474c113d3fd4
Author: Chris Tweney <chris@media.berkeley.edu>
Date:   Tue Jul 15 14:14:32 2014 -0700

    CLC-3921 Get courses and their schedules in a single query
Merge pull request #2699 from raydavis/raywip

CLC-3960 Reduce redundancy in memcached (prep work)
CLC-3921 Fix failing test
Merge pull request #2700 from ctweney/clc-3921-deletes-squash

CLC-3921 Implementing full delete support plus full-stack integration test
merging new ets changes