Add a layout engine that allows eliding sections of an array.

[mheinsen]

Using the current layout engines large arrays, and particularly multidimensional arrays, are displayed poorly. This is particularly bad for the case of using a large fixed size array when the number of used elements is dramatically less than the fixed size. One method that could help to deal with this is to allow eliding sections of an array. This will require some extension to the layout engine system, to be able to pass in values/properties to a specific layout engine (or the current layout engine being used for a specific Value).

[mheinsen]

Perhaps we should make this an option that all layout engines support (to some extent), so that the integration with the HTML/JS rendering is cleaner. In this way we would elide the individual Values representing the array's elements, and any value layout engine that renders arrays would have to honour that.