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/SkeletonHierarchy.cpp

@@ -63,7 +63,7 @@ int32 CHierarchy::FindNodeIndexByName(const char* name) const
 const CHierarchy::SNode* CHierarchy::FindNode(const char* name) const
 {
     int32 index = FindNodeIndexByName(name);
-    return index < 0 ? NULL : &m_nodes[index];
+    return index < 0 ? nullptr : &m_nodes[index];
 }
 
 void CHierarchy::CreateFrom(IDefaultSkeleton* pIDefaultSkeleton)

Code/Editor/Animation/SkeletonMapper.cpp

@@ -56,8 +56,8 @@ void CMapper::ClearLocations()
     uint32 count = uint32(m_nodes.size());
     for (uint32 i = 0; i < count; ++i)
     {
-        m_nodes[i].position = NULL;
-        m_nodes[i].orientation = NULL;
+        m_nodes[i].position = nullptr;
+        m_nodes[i].orientation = nullptr;
     }
 
     m_locations.clear();
@@ -141,7 +141,7 @@ void CMapper::Map(QuatT* pResult)
         }
 
         CHierarchy::SNode* pParent = pNode->parent < 0 ?
-            NULL : m_hierarchy.GetNode(pNode->parent);
+            nullptr : m_hierarchy.GetNode(pNode->parent);
         if (pParent)
         {
             pResult[i].t =
@@ -173,7 +173,7 @@ void CMapper::Map(QuatT* pResult)
         }
 
         CHierarchy::SNode* pParent = pNode->parent < 0 ?
-            NULL : m_hierarchy.GetNode(pNode->parent);
+            nullptr : m_hierarchy.GetNode(pNode->parent);
         if (!pParent)
         {
             pResult[i].q = absolutes[i];

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()