Editor code: tidy up BOOLs,NULLs and overrides pt1.

A few 'typedefs' replaced by 'using's
This shouldn't have any functional changes at all, just c++17 modernization
It's a part 1 of a split #2847

Signed-off-by: Nemerle <nemerle5+git@gmail.com>

Code/Editor/Controls/BitmapToolTip.h

@@ -42,7 +42,7 @@ public:
     CBitmapToolTip(QWidget* parent = nullptr);
     virtual ~CBitmapToolTip();
 
-    BOOL Create(const RECT& rect);
+    bool Create(const RECT& rect);
 
     // Attributes
 public: