Haiku: Control: Add missing setSize() implementation
Pull base class HaikuViewControl out of HaikuViewComposite
Haiku: Implement Button support

Not fully complete yet. Missing are:
* Image support.
* "grayed" support for SWT.CHECK style buttons.
* NO_RADIO_GROUP support.
Haiku: Fix missing radio button deselection event
Haiku: Button: Add support for SWT.NO_RADIO_GROUP