refactor(kff.createObject, kff.classMixins): performance optimizations

Use direct __proto__ overwritting where possible, then Object.create and lastly new function prototype rebinding, because __proto__ is much faster in Firefox than Object.create.

Small optimization in kff.classMixins.f (preprocess args outside returned function).
refactor(kff.View): performance optimization: use prototype link between models in the cloned view and the original view instead of copying all the model properties into separate object.
refactor(kff.View): use Object.SetPrototypeOf when cloning view models (if exists)
refactor(kff.createObject, kff.View): get rid of __proto__ and Object.setPrototypeOf

Direct setting of __proto__ is controversial and it doesn't make significant performance boots, it is even slower than copying properties from one object to another in some cases. Object.setPrototypeOf is faster in Chrome, but slow in FF (and it's only present in fresh nightly builds of Chrome and FF). Chrome is fast anyway, so I prefer getting better performance in FF with "safe" programming methods.
refactor(kff.Binder): delegateEvents and undelegateEvents methods can be called directly instead of using slower .call() function
refactor(kff.View, kff.BindingView): remove setParentView calls from clone methods

setParentView method was called multiple times in deep cloned view hierarchies because each cloning involved cloning in nested views as well and then again when cloning subviews etc. The solution is to remove any redundant calls in clone method (even reseting parentView in constructor to null) and call it once only on root of cloned view tree in BindingView.
refactor(kff.View): replace slice(0) by slice() when cloning arrays