Changed code so that it compiles in visual studio

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%402631

dlib/member_function_pointer/member_function_pointer_kernel_1.h

@@ -83,7 +83,7 @@ namespace dlib
                 // This is here just to validate the assumption that our block of memory we have made
                 // in mp_memory.data is the right size to store the data for this object.  If you
                 // get a compiler error on this line then email me :)
-                COMPILE_TIME_ASSERT(sizeof(*this) <= mem_size);
+                COMPILE_TIME_ASSERT(sizeof(mp_impl_T) <= mem_size);
                 clone(buf);
             }