minor cosmetic

Signed-off-by: JB Touchard <jbt@txtnet.com>
Some cosmetics + Categories added

side document is rem(ed) in all three QTIs
I added Math & History categories.
On this last point, it would be really nice to move the categories JSON from hard coding to a Mongo collection...

Signed-off-by: JB Touchard <jbt@txtnet.com>