Dark Heresy/Rogue Trader support
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

DH and RT systems use a d100 die, the result is compared to a target number
with some modifiers. You can roll a die using 'vs(40)' or 'vs(40+20-10)'
syntax. Unlimited number of modifiers is supported. The result is displayed as
the threshold value minus the roll value, so a positive number means success
and tens digit equals the number of degrees of success/failure.
You can roll several identical tests using syntax '3vs(30)'.
