Branch for 2nd try at V2 removal

svn path=/branches/filesystem-v3a/boost/functional.hpp; revision=77497
Abandoned when it became obvious that removing filesystem V2 from trunk (as a series of three commits) was much easier and safer wrt history than pursuing a single commit solution.

svn path=/branches/filesystem-v3a/boost/functional/forward_adapter.hpp; revision=77584