Force HTTPS for the entire site

* We already support HTTPS
* The data on the site includes protected information like grades
* We only use the *.appengine.com site url currently
* Leaves no reason not to be using HTTPS everywhere
Merge branch 'master' into force_https

Conflicts:
	src/main/webapp/WEB-INF/web.xml

Conflicts resolved automatically by mergetool
Merge pull request #260 from curtisullerich/force_https

Force HTTPS for the entire site