Better logging and error checking to help determine why we get
some backfill errors.
Fixed logging. The timestamps need conversion before going to ctime().
With the filter in place I can't log warnings from the Memcache related
code.
Document the memcached options required for reliable operation.
if we can't put data in memcached that's definitely an error
Merge pull request #25 from esnet/backfill_investigation

Fixes for the backfill problem.

* Better logging and error checking to help determine why we get
* Fixed logging. The timestamps need conversion before going to ctime().
* With the filter in place I can't log warnings from the Memcache related
* Document the memcached options required for reliable operation.