refactor(kff.View): rewrite recursive DOM "tree walker" algorithm to iterative
refactor(kff.View): create method nextNode for iterative DOM "tree walker"
refactor(kff.ClassBinder): non-strict compare to null
feat(kff.View): allow using model keypath in model events

When declaring model events, it should be possible to use model keypath as the first argument (not just model name), i.e.:

['foo.bar', 'change:attr', 'method]