Implemented full hierarchical inheritance of any controller event

[tristanls]

Because pull request #34 is still pending and I don't want to overwhelm the review process I'm holding off on submitting this feature till #34 is resolved. But you can look at the code on my fork https://github.com/tristanls/agility

This future pull request implements hierarchical inheritance of controller events. It allows us greater reuse of agility objects and enables construction by composition. Here's what that means:

var label = $$( {}, '<span data-bind="label"/>' );

var labeledElement = $$( {}, '<div/>', {
  'create': function() {
    var lbl = $$( label, { label: this.model.get( 'label' ) } );
    this.append( lbl );
  }
});

var labeledValue = $$( labeledElement, {
  controller: {
    'extend:create': function() {  // <- notice the 'extend:' syntax, this is *hint* to the framework to extend instead of overriding
      var value = $$( label, { label: this.model.get( 'value' ) } );
      this.append( value );
    }
  }
});

var myLabeledValue = $$( labeledValue, { label: "myLabel", value: "myValue" } );

<div><span data-bind="label">myLabel</span><span data-bind="label">myValue</span></div>

[tristanls]

Well, I guess these commits got automatically added to the previous pull request. Sorry for the confusion, still working on the finer points of github. This issue is now part of #34