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.
It's your PR. I've just modified your code to make it easier to read. Honestly I don't even understand what you've changed in code and how exactly it helps in solving the problem.