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
Merge pull request #2699 from raydavis/raywip

CLC-3960 Reduce redundancy in memcached (prep work)