Bugfix maxHeight after $.colorbox.resize()

Earlier, if I set .colorbox{maxHeight:'95%'...} then colorbox frame gets vertical scrollbar (if content is heighter than frame) but if then I do $.colorbox.resize() my colorbox frame becomes heighter than wrapper page and my maxHeight option is ignored, so this is bugfix for it.
Great, please make necessary adjustments to your PR code then. Also don't forget to squash the commits.