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.
oiiotool --frames and --framepadding give more wildcard flexibility.

When using oiiotool with numeric wildcards ("foo.#.exr"), rather than
rely strictly on matching exiting filenames, the --frames option allows
for explicit flexible frame sequence specification, and --framepadding
overrides the default number of digits (with leading zeroes) for frame
numbers. Examples of frame sequences now supported:
    10,11,13,14       Commas separate subsequences
    10-14             Range
    10-14x2           Range with step (matches 10, 12, 14)

Putting it all together, you can have a command like

   oiiotool --info --frames 10,18,20-30x5 --framepadding 3 foo.#.exr

would match foo.010.exr, foo.018.exr, foo.020.exr, foo.025.exr, foo.030.exr
IBA::resize speedups
(1) switch to fully specialized, Iterator-based
(2) parallelize!
(3) adjust filter radius, it was rounding up too high
oiiotool speedup: for not-huge files, force a read of the whole image up front.

oiiotool in particular tends to need all of an image at once, and with
many cores will parallelize across one image operation (say, resize).
If it's a cached-backed image, that means lots of threads are reading
tiles from the same open image file, and they will lock against each
other for control of the file handle.  That severely limits the thread
efficiency of ImageCache, in ways that would not be a problem if the
threads weren't all trying to read from the same file.  We combat this
by forceing a full read of the file into the IB up front, if it's not
too big.  Big files will still fall back to the ImageCache.  This
strategy is not for all apps, but for oiiotool's usage pattern in
particular, it really helps.
CHANGES and version bump for 1.1.9
Rebuild PDF docs