Inherit max_size properties for children of VBox and HBox widgets

[ChrisOelmueller]

• add a Label(wrap_text=True) to a VBox with a defined max_size
• => it is not wrapping anything unless you add the same max_size to the Label itself

If I set Label(max_size=(150,42178), wrap_text=True), everything is fine for VBoxes (and similarly (42178,40) for HBoxes) but in my opinion, a widget should check for the max_size of parent widgets since this size will be the limit anyways

[prock]

Moving to 0.3.5 as we are preparing to release 0.3.4