Added Bindable.bindable() method to enable the creation of bindable
properties that don't use get() and set()
Simplified Bindable and Hash in hope we can eventually deprecate get/set
methods, bumped to 1.5.0
All classes now automatically propertize themselves (convert 'get_name'
and 'set_name' methods into 'name' property)
Added propertize example; removed underscore.js from HTML in all
examples; resolved Application init issue preventing namespace being
specified in class; enhanced isDefinedProperty utility method to detect
non-existant properties