TODO for toxy
  * widget
    . cached handlers
    . better megawidgets
    . editor: handle semicolons (need to revisit resolution rules)
    . editor: differentiate argument keys from casual #strings (color-names)
  * tow: canvas-wide and type-on-canvas-wide broadcasting

DONE for toxy

alpha16
  * widget:
    . editor for options, handlers and arguments made more or less functional
    . better 'redefine' (although still only external types may be redefined)
  * tow:
    . fixed handling of gop-ed targets and missing windows
    . new messages: 'retarget', 'pwd'
  * tot:
    . scriptlet editor improved a little bit (still unfinished)

alpha15
  * fixes for megawidgets
    . setting sub-item bindings in ::toxy::subwidget
      (to be called explicitly from type initializer)
    . handling widget's state through virtual events
    . getting implicit geometry (needed for Frame widgets)
    . automatically rebinding focus for Canvas widgets

alpha14
  * 'redefine' message to widget
  * version control, using package provide (both in tcl and parsed from pd)
  * "> master" section removed:  master initializer defined directly
    by proc ::toxy::master
  * better kb: chords (shift-click), latch (control-click), dragging

alpha13
  * @new and @free handlers, defined in #@ new and  #@ free sections,
    invoked by widget object creation and destruction
  * optional sections #@ ini (aka #@ vis) appended to initializer (which still
    defines in default section too -- old .wid files do not need updating)
  * .#args parameter of message handlers, replaced (during scriptlet
    evaluation) by all arguments of an invoking message