Add basic support for Mac OS X
Use DCTImageCacheImage typedef for Mac support
Import CoreGraphics
Enable modules
Merge branch 'master' of file:///Users/danielctull/Dropbox/.gitbox/repos/DCTImageCache

Conflicts:
	DCTImageCache/DCTImageCacheAttributes.h
	DCTImageCache/DCTImageCacheAttributes.m
	DCTImageCache/_DCTImageCacheCompletion.h
	DCTImageCache/_DCTImageCacheMemoryCache.h
Add function to get an object representation from a size