Don't bother compressing assets, GZip should do.

@ojacobson argues that it's a bit of cargo-cult programming to minify
or yuglify your assets. Whether that's true or not, for the purposes
of this project, compression is likely to cause more problems than
solve issues for now.
Added Boto backend, even though Boto doesn't work.

Gonna replace it with something that does. Just a moment.
Refactored sheets unittests.

Added a custom `logged_in` decorator.