Fixed: CPPopover doesn't change his frame when with setContentSize

Previously when we changed the contentSize of an open popover, nothing happens.
Now, we the frame change and it's animated if needed
Fixed: setContentSize doesn't work when called several times

Previously when calling setContentSize several times, the final frame of the view was wrong.
I removed the animation as well. This doesn't work, and need a lot more of implementation.
Merge branch 'PopoverContentSize' of https://github.com/Dogild/cappuccino into Dogild-PopoverContentSize
FIXED: setContentSize: to work when no window is initialized yet
Merge pull request #2112 from Dogild/PopoverContentSize

Fixed: CPPopover doesn't change his frame when changing the contentSize