Alpar Juttner <alpar@cs.elte.hu> [Thu, 04 Aug 2011 21:47:29 +0200] rev 950
Merge #382
Alpar Juttner <alpar@cs.elte.hu> [Tue, 02 Aug 2011 18:13:34 +0200] rev 949
Allow lgf file without Arc maps (#382)
A single '-' character in the @arcs sectio header indicates that
there is no arc map.