[ISSUE-25] - Colorfast resizing of non-linear RGB images.

Probably a little too general in that it assumes any non-linear RGB image space is going to get screwed up by the resize, but who knows, it's imagemagick. Better to assume it always does the wrong thing.

Could add a regression test for this if you want - it would just have to compare swatches of a resized sRGB image to the original pixel values. Would probably just be a small sample patch from the original test image.

Also adds `*.egg` to gitignore for `pip install -e` and quick-fixes some things in demo-program that made it not work correctly.

Closes Issue #25.