Property maps can now be obtained as such:

         weight = g.edge_properties['weight']
         print weight[v] # v is a Vertex object
         weight[v] = 2.0
         # and so on...

The list of properties is obtained from g.vertex_properties,
g.edge_properties and g.graph_properties, which can be read as
dictionaries. The last can be set also, as such:

         g.graph_properties = {foo:"bar", baz:42}

Functions to add and remove vertices or adges were also added
(add_{vertex|edge}, remove_{vertex|edgge}).

Vertex and Edge types can also now be printed for convenience, as such:

       for v in g.vertices():
           print v
       for e in g.edges():
           print e

which results, for example, in:
0
1
2
3
4
5
6
(0,1)
(1,2)
(2,6)
(3,4)
(4,5)
(4,2)
(5,6)
(6,1)

(this also adds the forgotten graph_tool.py file, which was previously
on .gitignore)