Updating modal to allow bindable fade and backdrop

This update does require the built-in bootstrap.js but it seems to make more sense than re-creating existing functionality.  it also allows you to listen for the various namespaced bs events (using an eventManager)

apologies if this has been discussed elsewhere, but I'm not sure why this collection doesn't leverage the bootstrap.js libraries.  These are often included anyway to ensure UI elements are working.
This seemed to be a small bug wherein the isAriaHidden was returning the opposite of the visual state.