Mergeing extendermerge branch
Changes:
the extender system
resize for static size graph
UGraphExtender => UndirectGraphExtender
UGraphExtenders with changed meaning
Some UGraphExtender /SubUGraphExtenders, DirectUGraphExtender/
GridGraph => GridUGraph
radix sort to ansi compatible

/*!

\page ugraphs Undirected graph structures

The primary data structures of LEMON are the graph classes.

Under construction.

*/