First round of changes to refactor export code to use Quartz and CoreImage

First round of changes to refactor export code to use Quartz and CoreImage

Use Quartz and CI routines to get the image metadata out of the image before
scaling the image (which nukes the metadata). Use Quartz/CI to add select
IPTC fields to the image such as keywords/description etc...  Still need
to refactor the scaling code to use CoreImage routines (maybe the Lanczos transform filter?)
instead of the current (wasteful) quicktime solution.

This change not only allows us to embed keywords/description etc.. into the IPTC data sent
to Ansel, but it also will preserve much more of the metadata the the QT routine did.