Async filter

[rolaveric]

To take this example up to 11, going to need something equivalent to the 'async' pipe from the Angular 2 examples.

The common solution is to use a stateful filter:
http://stackoverflow.com/questions/19046641/asynchronously-initialize-angularjs-filter

[rolaveric]

Solved with 0d2bea0

Works by using the Model.getCache() method to get the data synchronously from the local cache. If said cache value is undefined, it makes a request with a safeApply($rootScope) on the observable, which then causes the filter to be rerun.
Rather than calling the filter async, I called it getValue (prefixed as rol_getValue) since it's specific to calling Model.getValue(), rather than being generic to all observables.

The problem with the generic observable solution is that each time the $digest loop runs, you have a new observable object to deal with. So you can't even create a mapping to substitute the correct value later.

Also created a pageRange (rol_pageRange) filter to help when dealing with a range of objects.
For example: You know there's a todos array in the JSON graph, but you can't retrieve the whole thing from FalcorJS. But you can retrieve it's length. And since length could be a huge value, you select a range of indexes from 0 to length - 1.

ng-repeat="index in 'todos.length' | rol_getValue:model | rol_pageRange:currentPage:pageSize"

Syntax could use some sugar, but it's sound.