Update dement.kod

Cuts the duration of dement from between 5 and 30 minutes to between 50 seconds and 3 minutes.

The spell currently completely shuts down casters and 3 minutes is still longer then most battles. So dement is sill nasty strong but at least now you don't have to camp online after a fight waiting for it to fade if you're not shal.
Merge pull request #141 from theanax/Dement-Duration-Cut

Dements Duration