BGL subgraph "put" function

From: Douglas Gregor (gregod_at_[hidden])
Date: 2001-12-06 15:51:05

Hello,
  The subgraph parameter for the "put" function in subgraph.hpp is passed as 
a reference-to-const subgraph, so it is impossible to modify a property value 
given a subgraph. Removing the const and retrieving the non-const property 
map type fixes the problem (see attached patch).

        Doug