review: deferred updating of html dom in renderers

[gabor-farkas]

Related to #72

1. the user clicks the checkbox
2. the model value is set to true
3. the presenter binding listener is invoked, and the presenter value is set to true
4. the application code is invoked, and the presenter value is set to false
5. the presenter binding listener is invoked, and the model value is set to false
6. the renderer reacts to the model value change and unchecks the checkbox in the dom. This is the bottom of the orignial call stack.
7. now the methods return in the stack to 3)
8. After the presenter binding is invoked, the renderer listener is invoked with the original true value, so the dom is updated to the checked value.

This causes that the checkbox remains checked, although the presenter logic updated the viewmodel to false. This is because the event loopback is at the top of the stack.
#72 was solved by changing the way the renderer handles model changes: it doesn't instanlty update the html dom, but defers and udpater. The updater will rely on the model value, so it passes by any transient change. This ensures that the correct viewmodel value will be reflected in the html dom.

We'll need to revise other renderers to conform this scenario.