This commit was manufactured by cvs2svn to create branch
'graph_devel_1_33_0'.
Added several algorithms:
  - random graph layout
  - Fruchterman-Reingold layout
  - A* search
  - Floyd-Warshall all-pairs shortest paths

Fixes for several algorithms:
  - Documentation for Johnson all-pairs shortest paths
  - Bellman-Ford single-source shortest paths
No need to * Floyd-Warshall