Added option to export original images, instead of edited ones

Exporting original images could be desired in a lot of situations, but this addition came out of realizing this: 

iPhone photos are taken upside down, with an orientation flag set in the exif data to allow them to be displayed in the proper orientation. That's true for a lot of cameras, not only the iPhone.

iPhoto 9.4.3 actually rotates and recompresses these images, and stores them in the iPhoto library under ImagePath as an edited image. This is true even if you yourself hasn't done any editing on the photo.

This means that using the script without setting the -o option, exports the recompressed version from ImagePath, not the original pristine copy.

When reviewing, take extra note of line 405-415: here I just followed in the footsteps of the last person editing, unsure exactly how that effects the actual export.