Fix to FreeImage.h for OSX and iOS for typedef problems, replaced with define/undef

Based on the original changes ofTheo did 3 years ago.
https://github.com/openframeworks/openFrameworks/blob/e1de1d53a9de4f7efe
1af9f028271ff13d508aae/libs/FreeImage/include/FreeImage.h

Updated for the new version and to support the new 64bit data structures