Fixes setVisible(false) for 2D controls without forcing all controls to be re-drawn.
Issue #751.  Layout::align() takes a control's margin into account.
This change also adds a bottom-right-aligned button with margins to the basic form controls test.
Merge branch 'next' of https://github.com/blackberry/GamePlay into next

Conflicts:
	gameplay/src/Form.cpp
Reverting gameplay/.cproject
Merge pull request #755 from ablake/next

A couple UI fixes.