Weapon Trait not being calculated for the post-roll modifiers

[DasSauerkraut]

If one of the actors in an opposed roll uses the weapon trait, the test won't calculate things like size bonus, weapon length, etc.

Fixing this will assume that for medium creatures the weapon counts as average. For each size step above or below medium, the weapon length will increase/decrease by one step. Ex. a Large monster's weapon trait will be Long.