Dark Heresy/Rogue Trader/Deathwatch support
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DH/RT/DW 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)'.