Interface Kit: Adjust max size and default alignment...

...on controls where it makes sense:
- BRadioButton and BCheckBox now return their preferred size as their
maximum.
- BRadioButton, BCheckBox and BTextControl now use left alignment by
default, as this is the most common use case for them.

headers/os/interface/RadioButton.h

@@ -61,7 +61,7 @@ public:
 	virtual	status_t			Perform(perform_code d, void* argument);
 
 	virtual	BSize				MaxSize();
-
+	virtual	BAlignment			LayoutAlignment();
 
 private:
 	friend	status_t			_init_interface_kit_();