Log Message:
updated to 0.07.

Changes from 0.05:

0.07 Mon July 18, 2005
    - forgot to implement the node filter in the
      Tree::Simple::Visitor::VariableDepthClone visitor
        - added this code and tested it

0.06 Wed July 13, 2005
    - added Tree::Simple::Visitor::VariableDepthClone
        - added tests and docs for this
        - bumped up the Tree::Simple version requirement to
          support this new Visitor