Move the put_in_background() function from iv private into sysutil.
Make OPENEXR_VERSION and ILMBASE_VERSION available in cmake-gui to use
newer OpenEXR versions (like 1.7 and 2.0) change FindOpenEXR.cmake so it
would also find the includes with newer versions of OpenEXR -
OpenEXRConfig.h is not included in newer OpenEXR deployments
Update ref image
Remove old Boost <1.40 vestiges.
This includes deprecating hash.h, which is no longer needed and removing
boosttest.h, which has not been used at all for some time.
ImageBufAlgo::over and oiiotool --over
More 'over' changes from LG atop Stefan's code:
* Lots of documenting comments.
* Some minor formatting changes or other small changes for clarity in
  some places.
* Move parallel_image to imagebufalgo.h and change slightly to remove the
  need for the R parameter entirely. I think that makes it even more
  generally useful.
* Add testsuite/oiiotool-composite
* Fix oiiotool default threads to correctly be hardware concurrency.
Merge pull request #390 from lgritz/over

ImageBufAlgo::over() Porter/Duff compositing operation and oiiotool --over
by Steven Stavrev (with minor LG mods)
Open PNM files in binary mode

In ascii mode, the "pnm.imageio" plugin sometimes fails to read binary
format PNM files (when it encounters an unsigned char of value EOF).
Conversely, reading ascii format PNM files in binary mode is OK.
Handy time_trial template runs function n times, reports best time and range.
atomic_test and spinlock_test: add multiple time trials, wedges of numthreads, and other refactoring.
New spin_rw_test: test and times spin_rw_mutex.
Macros for memory and cache alignment
Merge pull request #382 from lgritz/lg-threadtests

Improved threading unit tests and time trials, alignment
Make IBA::over() support only float buffers -- faster compilation and simpler source.
But internally, there is still a type-specialized template supplying the
guts of the algorithm, so in the future, we could expose it if there's demand,
or of course anybody may copy that template to their app if they are allergic
to float ImageBuf's.
Fixes quantize (before it was just truncating)
Minor fixes for over

Two fixes:

1. In imagebuf.h the const iterator
was taking non-const ImageBuf so I fixed that.

2. I moved the type checking code in ImageBufAlgo::over
at the top of the function, no need to come at the
end of the function to realize types are wrong.
Fix iv Qt moc dependency
Add ImageBuf::specmod() to give access to writable spec. Use caution.
Have ImageBufAlgo::capture_image put the capture date/time in the metadata.
Move iv local "copy_pixel_channels" into ImageBuf::get_pixel_channels.
Then re-implement IB::get_pixels in terms of it.