Switched the %'s for health, food and the level over to slightly more user-friendly variants

Signed-off-by: Toon Schoenmakers <nighteyes1993@gmail.com>
Added support for %xp and %xplevel

%xp results in something like 0.23432 which is just the amount of
xp. %xplevel is the level + the xp, so something like 28.23433

Signed-off-by: Toon Schoenmakers <nighteyes1993@gmail.com>