[ALOY-432] add destroy() function to all controllers

*IMPORTANT*: Calling destroy() will be critical for preventing memory leaks in alloy code that employs model-view binding. We will be adding a *destroy()* function to all controllers. Under the hood this will be added as:

exports.destroy = function() {
    // auto-generated destroy code
}

In its initial form, the destroy() function will be used only to remove event listeners tied to global and local references to models/collections, which are created when model-view binding is employed. A typical example of using it would be when you close a controller's window if it or any of its UI components used model-view binding.

$.win.on('close', function() {
    $.destroy(); // clean up binding
});

This will prevent any possible memory leaks, specifically when making bindings against a global model (Alloy.Models) or collection (Alloy.Collections).