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/Demos/WidgetGallery/DemoWizardPage2.gml

@@ -9,8 +9,8 @@
         fixed_height: 32
     }
 
-    @GUI::ProgressBar {
-        name: "page_2_progress_bar"
+    @GUI::Progressbar {
+        name: "page_2_progressbar"
         fixed_height: 28
     }