Fixed: Sheet window under the toolbar

Previously when using a sheet window in a fullPlatform window, the sheet window started the animation under (the layout) the toolbar.
Now, the sheet animation starts below the toolbar as in cocoa.
It also fixed that only a CPBordelessWindow/CPTitleWindow/HUD can have a toolbar.
Added CPBorderlessBridgeWindowMask for the ToolBar
Removed on pixel at the top of a sheet window
Merge branch 'WindowSheet' of https://github.com/Dogild/cappuccino into pr-1918