[ALOY-191] Alloy model verification app

update

The "models/todo" test app will likely be used as the app by which sync adapters should be verified.

original ticket

Instead of having separate test apps for all of our model adapter: * sql * properties * localStorage we should probably have a single validation app that confirms that the adapter fundamentally works. A good candidate would be the app that currently validates the properties adapter, as it makes use of single models, models in collections, and user interactivity that creates, deletes, and modifies models and collections. That sample can be found here: https://github.com/appcelerator/alloy/tree/master/test/apps/properties_model This will allow us to assert that our existing adapters, and any future adapters, perform all of the core functionality that is necessary of all adapters. We can still have separate apps for each adapter if we feel it is necessary to show off adapter-specific functionality, like queries in SQL for example. Right now, though, none of our current adapter test apps show any adapter-specific functionality and are thus not necessary if all adapters run as the current properties_model app does.