[whitespace] tabs -> spaces
Create a nav bar [#11]

* The stuff that was previously in <header> is now in <div.page-head>.
* Login is now in the header.
* The add-images link is now in the header.
* You can no longer view the add-images page at all when logged out.
Redirect to the current path after login [#13]

Upgraded flask-openid in the midst of debugging; the new wersion has
some security fixes so it stays.

Using g.user in layout.html.jinja instead of a local user variable
determines logged-in-ness correctly for all routes, regardless of
whether they pass in a user variable.
Use g.user in all templates, not a local user var

This just avoids an obnoxious class of problems where the user is
correctly logged in, but the controller forgot to tell the template.
Add some basic tests for logged-in display [#11]

(the changes in e50b28d6d94dc7e06b6828f941ccf40495dad8fd)
 Merge branch 'nav-header' into 'version-5'

Nav Header

Fixes #11
Fixes #13