Add opportunity from browse view

Before, only the new project button worked.
Now you can click the +Opportunity button, and a new
orphaned opportunity will be created.

A few tricky things with this:
- Modal is implemented differently than ModalWizard, which doesn't
  create its own div.  These methods should be unified in the future
  to prevent confusion.
- Instead of using the hacky setTimeout() function, we now bind
  to the bootstrap modal hidden event.  This lets us know when
  the modal has successfully gone away, and we can navigate to
  the next view.  Failure to do this leads to a broken page
  where it is grayed out or scrollbars don't work.

This was a lot more tricky than I thought it would be, but it works.