Add clang-format file

Also run it across the whole tree to get everything using the One True Style.
We don't yet run this in an automated fashion as it's a little slow, but
there is a snippet to do so in makeall.sh.

DevTools/VisualBuilder/VBWidgetType.h

@@ -1,6 +1,7 @@
 #pragma once
 
-enum class VBWidgetType {
+enum class VBWidgetType
+{
     None = 0,
     GWidget,
     GButton,