Masterview devel - Sep 2006 - Redoing DirectiveDSL as a mixin rather than base class for DirectiveBase

... turns out to be pretty simple adjustment to what you''d already
done.

Preview stored in branches/djl-namespace-additions-sketch/directive_dsl.rb
(includes namespace experiment, which you may or may not yet want in the
trunk)

Mods are:

(1) DirectiveDSL is now a module, rather than a class.

Replace:
    class << self
      include DirectiveDSLClassMethods # create class methods
    end

with notification handler which is called when mixin include happens:

    # add class methods for DSL declarations to class which is mixing in
DirectiveDSL
    def self.included(mixing_class)  #:nodoc:
      mixing_class.extend(DirectiveDSLClassMethods)
    end

(2) change DirectiveBase decl from:

  class  DirectiveBase < DirectiveDSL

to:

  class  DirectiveBase
	include DirectiveDSL

And that seems to do it.  Unit tests all run, ditto quick check of a test
app.

~ Deb