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/Animation/SkeletonMapperOperator.cpp

@@ -37,8 +37,8 @@ CMapperOperatorDesc::CMapperOperatorDesc(const char* name)
 CMapperOperator::CMapperOperator(const char* className, uint32 positionCount, uint32 orientationCount)
 {
     m_className = className;
-    m_position.resize(positionCount, NULL);
-    m_orientation.resize(orientationCount, NULL);
+    m_position.resize(positionCount, nullptr);
+    m_orientation.resize(orientationCount, nullptr);
 }
 
 CMapperOperator::~CMapperOperator()