Expand 'ZK' tag to support MVVM approach

The current ZK tag implementation uses EL related syntax with 'ForEach' and other options for generating blocks of repeating ZUL content. It provides a nice way of programmatically generating markup.

Unfortunatley this doesn't fit well with the new MVVM approach, especially the lack of support for data binding.

I'd like to see extra facilities added to the ZK tag so that it can take MVVM annotations like..

model="@vm.myList"