0.04 - Can now handle filehandles connected to memory objects.

0.03 - Rewrite the existing functions so that they die if:
       1) the received  argument is not an open filehandle;
       or
       2) the received argument is a filehandle connected to a memory object.

     - Add the is_arg_ok() function. 

0.02 - Minor changes for compatibility with pre-5.6 versions of perl, and some tidying up.

0.01 - ummm ....