improving user experience when failing to sign up due to no facility.

Current UX when clicking "sign up" before an admin has added a facility assumes that it's an admin trying to sign up.  However, I think (a) that's not necessary, (b) that's not likely, and (c) we should support the case where no facility is ever created.

To do that, instead of emitting admin-focused errors and redirects, do something that makes sense for both.  See "before" (old behavior) and "after" (new behavior) screen shots below.  I think this makes more sense for end-users.

Before (Clicked on "Sign up"):
![screen shot 2013-06-29 at 12 07 06 pm](https://f.cloud.github.com/assets/4072455/726367/e8963064-e0ef-11e2-92a6-bec33e7f9e33.png)

Afte (clicked on "Sign up")r:
![screen shot 2013-06-29 at 12 07 43 pm](https://f.cloud.github.com/assets/4072455/726368/f036cef0-e0ef-11e2-85f9-7d59c6fb80f6.png)