Bump version to distinguish master from 1.1
Create option to use external (system) TBB.
imagespeed_test improvements:
1. --threads lets you test with different numbers of threads (default: 0,
   which means as many threads as cores available).
2. New iteration tests that include "slave" iterators, as we often use
   in ImageBufAlgo functions.
3. When more than one filename is provided, the read tests go through
   every file in sequence.  For the iteration tests, just the first file
   is used.
4. --autotile lets you set what size to test for autotiling.
5. --iteronly skips the lengthy image read tests, only times the iterators.
Speed up ImageBuf Iterators.

In this case, we are concerned especially about the following idiom that
we frequently use to traverse two images simultaneously.
    for (Iterator master(img1), slave(img2); master.valid(); ++master) {
        slave.pos (master.x(), master.y(), master.z());  // synchronize
        // do something with *master and *slave
    }
We repeatedly re-position the slave to the master's position, because there's
no guarantee that two iterators will advance simultaneously with ++ (among
other reasons, that the two images themselves may have different pixel data
windows, and thus different iteration ranges).

Re-positioning the slave on every iteration of the loop was a big time sink.

Improvments in this patch:
1. Have pos() recognize the common special case of incrementing x from
   its last position and still staying in the iteration range, and take a
   big shortcut for that case.
2. Cache the end x position of the tile in the iterator, for quick comparison.
3. Incidentally, migrate operator++ from Iterator and ConstIterator into
   the base class.
Remove DASSERT that was breaking debug compiles
oiiotool --info now recognizes --metamatch and --no-metamatch
These control which metadata are or are not printed with oiiotool --info -v.

--metamatch is followed by a regular expression showing which metadata
to print (the rest will be excluded from output).
--no-metamatch is followed by a regular expression showing which metadata
NOT to suppress (the rest will be printed).
It's probably not very wise or intuitive to use both together.
Allow test output to exclude certain metadata when printing image info.

This uses the --no-metamatch option recently added to oiiotool.
This is really handy for certain tests that involve dumping oiiotool --info,
to simply make it not print the fields that might change from run to run
(like DateTime), or release to realase (like Software) and thus make
spurious testsuite failures.
Fix minor bugs that let IBA::fixNonFinite work properly with 'half' images.
Add testsuite for maketx
Fix SHA1.cpp build problem on some platforms -- issue #473
Fix testsuite reference output
Break out maketx functionality into callable ImageBufAlgo::make_texture()
Change default to use new maketx mode (do NOT backport this to 1.1)
Perf - replace std::vector and its needless initialization with boost::scoped_array
Improve performance in all sorts of places by cleaning up convert_types:
1. Don't use tmp scratch space for nonfloat->float case (just do a direct
   convert from buffer to buffer)
2. If you must use scratch space, use stack if small, heap only if big.
3. Rearrange switch cases to have common ones first, impossible ones never.
4. Drop useless parameters (but provide one of the old signature for
   link compatibility).
TIFF output output when 'tiled' and 'separate' - fix buffer overwrite.
Not only do I allocate a separate buffer now, but I also put in smarts
to store it on the stack when reasonable size, dynamically allocate when
it's big, which should be a minor speed gain for the usual case.
RLA: Assume that any 32 bit aux channel is z
oiiotool --zover does depth compositing
Fix compiler warnings.
Change cstring to string to fix build issues -- fixes #206