Attempted to add Project 3, owsd.org template

I copied the images from owsd into a couple directories, but I always get a
404 when the site tries to find them.  The documentation for jinja is very
sparse, so I don't really have any indication of why this is happening.  I'm
guessing I need to individually server each of the images somehow, but that
seems outside the scope of this assignment.  The page loads with all CSS
properties working except for background-image.

Somehow my base.html changes from several homeworks ago got lost somewhere, so
I re-added that to all of my app's html templates.  This required updating
test_server.py.