Made the requires checking for array::set_size() always stay on since it is not

going to be performance critical and is a common user error.

dlib/array/array_kernel.h

@@ -364,7 +364,7 @@ namespace dlib
     )
     {
         // make sure requires clause is not broken
-        DLIB_ASSERT(( size <= this->max_size() ),
+        DLIB_CASSERT(( size <= this->max_size() ),
             "\tvoid array::set_size"
             << "\n\tsize must be <= max_size()"
             << "\n\tsize: " << size