Fix typo that caused incorrect IB::copy_pixels of mixed type.
Tweaks to the cmake build system (mostly for SPI):
* At SPI, build against OpenEXR 2.0 if available
* At SPI, update which internal Field3D build we use.
* At SPI, build against Boost 1.51
* New cmake variables that let you specify a custom OpenEXR & Ilmbase location.
* Some other cruft removal in the build system
Fix Makefile typo
ImageBuf::set_write_format and set_write_tiles lets you override the
data format and tiling to use when subsequently calling IB::write().
Read-from-file ImageBufs should get set up to cache on construction
Conform to new ImageBuf construction and write conventions
Minor reformatting
added BOOST_HOME and OCIO_HOME to override locations of boost and OpenColorIO
Replace ASSERT in ImageRec::read with a more gentle failure
DPX bug fixes:
* Was not handling nonzero image origins properly in DPX read_native_scanline.
* Apparently, some files have 0xffffffff in the 'originalSize' fields
  to indicate that they aren't used.
Add SPI regression test
CHANGES update, docs, bump version for 1.3.4 release
GIF error reporting - improved thread safety, and work for older libgif
Accommodate some changes in recent cmake for HDF5 finding
ImageBuf::roi() and roi_full() should be const
Revise Field3D release number for SPI internal build
ImageBufAlgo::resize/resample -- fix scaling problem for non-0-full-origin images
maketx handle inputs that are mixture of crop and overscan
CHANGES update, bump versin for 1.3.5 release
SPI is now building OIIO with clang-3.3.