Clean-up the address-bar after auth

The code and state parameters were hanging in the address-bar even when
the were not needed there.

Change-Id: Iadeaf4314fe4a7c260f2c03e8845377ad72b4ec8
Creating a new story now requires authentication.

The UI should not allow an unauthenticated user to create stories;
recording the identity of a reporter will allow us to communicate with them
to discover specifics about their requests. This commit adds a login modal
and controller in the auth package, which is hooked into the new story modal.

Change-Id: I62e6937f863c8d0f790d7bff7edd7335b9ac4653
Fixed padding on modals.

There's a trailing margin at the bottom of modals. This fixes it.

Change-Id: I75df76cb031c299fa051341342c83a1a3fd101d1
Added UI switches for authentication state.

When a user is not authenticated, many UI Controls should be hidden,
including "add" buttons, "edit" buttons, "delete" buttons. Furthermore,
during the transition of the session state (when someone logs in/out),
the UI routes need to re-resolve themselves to determine whether the user
is now on an invalid state.

Change-Id: I057c5e5db30a74edfe66c67b60d2c0b797da6561
Merge "Fixed padding on modals."
Merge "Clean-up the address-bar after auth"
Merge "Added UI switches for authentication state."