[css3-images] Updated Disposition of Comments

I've updated the CSS3 Images Last Call Disposition of Comments, which you can find here:
   http://dev.w3.org/csswg/css3-images/issues-lc-2012

Per the CSSWG resolutions this week, the sections on element() and the rtl/ltr
image() annotations have been dropped. All other issues should be addressed at
this point.

Note, I'm still checking the Object Sizing Algorithm section with Tab and dbaron;
I'll post an update on that once we're all happy with it. :)

~fantasai