Added DWAA/B compression options
Added DWA compression options to Windows dialog
IlmImf now depends on Half

Because of DWA LUT building phase
Add Xcode 5 projects
Switch to AEIO idle function

AEIO provides an Idle Hook, may as well use it.

Also did an audit of the different AEIO calls we may or may not be
getting.
IlmImf now depends on IlmThread and Iex
Update to latest OpenEXR library

Includes DWA compression
Merge branch 'develop'