FIX: Incorrect package name in clean-version
CLEANUP: Remove `control` submodule, these should be examples
ENH: Overhaul and refactor of image content & tests.

Improvements to test suite.

There was redundancy in `contrast` algorithms. No longer.
`image.focus` was contrast, not focus at all, and was
moved into `fuzzymath` replacing more primitive `contrast`.

`sigmoid` also moved into `fuzzymath`.