Fixed: Windows with toolbars do not display correctly as sheets

Previously it wasn't possible to display a toolbar in a sheet window.
Now, a toobar is displayed well in a window. This PR allows every sheet window to have a toolbar, with the PR #1918 just the CPTitleWindow/HUD sheet could have a toolbar as in cocoa.

Fixes #1863
Refactor code
Added test for toolbar sheet
Added theme for Arsito1
Updated test
Merge branch 'SheetToolBar' of https://github.com/Dogild/cappuccino into pr-1919