Don't want git to track experiments with ImageMagick
Improvements to showcase/slideshow

- Don't show the resizing in progress -- I'm pretty convinced that it
works ok now without having to see it happening.
- In slideshow mode, shift the center of the showcase to allow for the
width of the filmstrip.
Debug code to convince myself that igrid weirdness is not all that weird.
Commit inspected cell with no usable images should be the same as a banishment.
Fix fade in/out for image reload.
Software rot is an amazing thing. Recovery checkpoint.

We're back to the point where we can insert records in the db, although
they all have wrong keys and none of the correct field values.
Mayer inserts new records into the database now
What the heck happened here?
Get rid of duplicate checking for the moment.
Checkpoint before branch to bring mayer up to scratch
Just save it in case it's useful in the future
First test harness: TestChildIDRequirement
Complete test harness for Thread class
Strip Thread class down to just what a thread class should do. Thread client is responsible for everything else.