Simple uniform way to extract optional arguments from oiio commands
oiiotool --fit improvements: fix subtle bugs with aspect ratio preservation
for images with differing data and display windows; allow "filter=..."
option to select the filter (as originally advertised but not implemented).
IBA::resize() improvement -- instead of "clamping" at the image edge, just
don't consider nonexistant pixels at all. This solves some artifacts for
certain resize situations, as well as simplifying the logic.