fixed a but in ReplaceExtName that replace extname at .

inc/hgl/filesystem/Filename.h

@@ -350,7 +350,7 @@ namespace hgl
             const int pos=old_name.FindRightChar(split_char);
 
             if(pos!=-1)
-                return old_name.SubString(0,pos)+new_extname;
+                return old_name.SubString(0,pos+1)+new_extname;
             else
                 return old_name+String<T>::charOf(split_char)+new_extname;
         }

inc/hgl/math/FastTriangle.h

@@ -1,5 +1,4 @@
-#ifndef HGL_ALGORITHM_MATH_FAST_TRIANGLE_FUNCTION_INCLUDE
-#define HGL_ALGORITHM_MATH_FAST_TRIANGLE_FUNCTION_INCLUDE
+#pragma once
 
 #include<hgl/math/MathConst.h>
 #include<math.h>
@@ -73,4 +72,3 @@ namespace hgl
         return x*(1.12*x - 0.12);
     }
 }//namespace hgl
-#endif//HGL_ALGORITHM_MATH_FAST_TRIANGLE_FUNCTION_INCLUDE