Revert "Adding imagediff integration tests."

This reverts commit f199204dc2d545e2f1e08b1baf885ff09f57fb57.
Eliminating commented-out-code
Removing defaults pending guidance on API usage.
Adding demo of usage with simple builtins.
correcting label
Testing full range of user's margin option values. Tests failing.
Fixed bug in cacluateLegendOrigin revealed by new tests.