Unify pointers comparison, consistency asserts
diff --git a/tinyxml2.cpp b/tinyxml2.cpp
index c6845db..d4c45a4 100755
--- a/tinyxml2.cpp
+++ b/tinyxml2.cpp
@@ -2061,6 +2061,7 @@
     if ( _processEntities ) {

         const bool* flag = restricted ? _restrictedEntityFlag : _entityFlag;

         while ( *q ) {

+            TIXMLASSERT( p <= q );

             // Remember, char is sometimes signed. (How many times has that bitten me?)

             if ( *q > 0 && *q < ENTITY_RANGE ) {

                 // Check for entities. If one is found, flush

@@ -2084,11 +2085,13 @@
                 }

             }

             ++q;

+            TIXMLASSERT( p <= q );

         }

     }

     // Flush the remaining string. This will be the entire

     // string if an entity wasn't found.

-    if ( !_processEntities || (q-p > 0) ) {

+    TIXMLASSERT( p <= q );

+    if ( !_processEntities || ( p < q ) ) {

         Print( "%s", p );

     }

 }