Added myself into the copyright notice.

I'm not sure if this is the kosher or canonical way of doing this, but
it seems reasonable.
Update the usage help.
Updated to use Objective-C literals.
Updated to use ARC.
Don't hard-code the supported image file formats; just try every file and go with whatever works.
Removed redundant comment.
Clarified comment about NEF reliability when used directly.
Added the -sort flag, with the new default of by creation date.