Simplify.
Must expire the cache after the new log is written as well.

We clear the cache before writing new events to the log (in case
another process altered the history), but then immediately read
in (and thus cache) the log again - BEFORE the new data is written.
The new data was never present in the cached history.

Fixes (among other things) filtering out changes in activesync
requests that are the result of an incoming client change.
Not used.
Cleanup/fix some stat related logic.

Fixes properly logging the incoming client change in the appropriate
map table (email vs other collections) and thus detecting changes
that are due to incoming client changes for email data.
BFN
BFN