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).

 /*!

 \page ugraphs Undirected graph structures

 The primary data structures of LEMON are the graph classes.

 Under construction.

 */