Add configuration for death penalties

Closes #493

This includes:
* turning off death penalties all together
* forcing permadeath for all new characters
* removing a percentage of currency
* removing a percentage of total XP or a percentage of XP since the last
level up
* removing a random equipped/carried item

A note about removing XP. This commit does not support down-leveling
when removing XP. I figured it would cause issues with unlocked powers
(i.e. how to go about "un-rewarding" power points).