Use HUD style buttons in HUD style test window.
CPView _setThemeIncludingDescendants:.

This method makes it possible to e.g. switch a whole window to the HUD theme.

It's internal for now.
Feature to open the attached sheet test window in HUD mode.

This is not a bad kitchen sink test for HUD widgets and windows.
Refs #1754. Fixed: wrong button text shadow direction in Aristo 2 HUD theme.
Refs #1754 . Fixed: pixelated corners on Aristo 2 HUD windows.
Refs #1754. Crisp, pixel perfect CPAlert warning triangle.
Fixes #1754. Fixed: CPAlert ignoring keyboard interaction, not movable by background.

Without this fix, a CPAlert window couldn't actually become the key window which meant it couldn't receive keyboard events such as using the escape key to close the alert or hitting enter to activate the default button.

Furthermore the window could not be moved by clicking its background and dragging.

This fix makes CPAlert windows into CPPanels instead, which can become key windows and is more appropriate since panels are meant for auxiliary windows.
Merge branch 'master' of github.com:cappuccino/cappuccino