[Openexr] Little issue...

[Austin Benesh]

Hi everybody,

I found that with the current working implementation, Blender outputs 
OpenEXR images flipped. When it opens exr images output by itself, 
however, they appear unflipped. This is caused by a difference between 
organization of image buffers between the format and Blender. I'm going 
to write a flipping algorithm that will flip the imbuf upon output to 
OpenEXR and flip it again upon input into Blender. This should fix any 
flipping problems we have.

Just thought you should know. :)

    - Austin