Everywhere: It's now "Foobar", not "FooBar", and not "foo bar"

I hereby declare these to be full nouns that we don't split,
neither by space, nor by underscore:

- Breadcrumbbar
- Coolbar
- Menubar
- Progressbar
- Scrollbar
- Statusbar
- Taskbar
- Toolbar

This patch makes everything consistent by replacing every other variant
of these with the proper one. :^)

Userland/Services/WindowServer/Window.cpp

@@ -977,7 +977,7 @@ bool Window::hit_test(const Gfx::IntPoint& point, bool include_frame) const
     return color.alpha() >= threshold;
 }
 
-void Window::set_menubar(MenuBar* menubar)
+void Window::set_menubar(Menubar* menubar)
 {
     if (m_menubar == menubar)
         return;