[school-core] Screenshots in progress

[Justin Riddiough <jriddiough@xxxxxxxxx>]

I've added the field to the software form for uploading screenshots.
For an idea of the style it will be applied with, see
https://addons.mozilla.org/en-US/firefox/addon/fbxrev_downloader/
there is a sort of slideshow, fadein-fadeout presentation which is
nice.

We talked about using the NCOSE images for some of these, so maybe
that's a starting place.  With 'document viewer' / evince, I'm able to
right click the screenshots and save them to a file.

So for now we can start uploading, but the interface for viewing will
be set up later.  Thought it would be okay though, so we can go ahead
and get started.

Justin