An easy avoiding of a bug

The functional interfaces are removed.
Better solution could be a reference counted core of the io interfaces

Now it is huge work so just write that:

GraphReader<ListGraph>(std::cin, graph).

Instead of:

graphReader(std::cin, graph).

 Document: lemon-refman

 Title: LEMON Reference Manual

 Author: LEMON Development Team

 Abstract: Documentation of LEMON.

 Section: unknown

 Format: HTML

 Index: /usr/share/doc/lemon/html/index.html

 Files: /usr/share/doc/lemon/html/*.html