Revision history for Perl extension PNI::GUI::Tk.

0.15  2011-09-xx
    - del nodes
    - node inspector and node_selector improved
    - comment_editor
    - PNI::GUI::Tk::Canvas::Group

0.14  2011-08-08
    - write comments

0.12  2011-07-31
    - first usable version
    - open, save .pni files