Steven Ports authored Sep 06, 2013 and Luc Maisonobe committed Sep 06, 2013

This is an initial support, it needs some additional work to factor some
code between the three sub-formats end to provide consistent API (for
example some elements are available at very low level (individual
numbers) while others are already conveniently gathered in intermediate
classes (for examples maneuvers in OPM).

This is a long due feature, many thanks to Steven for having done this!

Fixed issue #13.