appropriate. This allows us to switch the exif value column back to
varchar and improves the way that we deal with non-utf8 data in our
embedded EXIF/IPTC data.
many separate queries.
In the process, rip out the summary column, we weren't using it.
Clean up the test, and drop the exif_records database on uninstall.
* Create Exif_Record_Model to track whether we've scanned the EXIF
data for this photo or not. This allows us to track photos that
don't have EXIF data (and won't have any Exif_Keys)
* Blow away old Exif_Keys when extracting, else we hit unique
index constraints.
* exif::_get_stats() -- before it was running the task forever
