Add more pointer pre-asserts
diff --git a/tinyxml2.cpp b/tinyxml2.cpp
index 4ce2184..57a82c1 100755
--- a/tinyxml2.cpp
+++ b/tinyxml2.cpp
@@ -663,6 +663,7 @@
 

 XMLNode* XMLNode::InsertEndChild( XMLNode* addThis )

 {

+    TIXMLASSERT( addThis );

     if ( addThis->_document != _document ) {

         TIXMLASSERT( false );

         return 0;

@@ -696,6 +697,7 @@
 

 XMLNode* XMLNode::InsertFirstChild( XMLNode* addThis )

 {

+    TIXMLASSERT( addThis );

     if ( addThis->_document != _document ) {

         TIXMLASSERT( false );

         return 0;