Strength functionality

[Dectilon]

There's no real stamina stat, so I figured sort of included both. Also, there's no strenght restrictions for use of specific weapons or armor, so I figured strenght of that kind wasn't relevant.

Could be interesting to have some weapons that require your strenght to be above or below a certain amount. For example there could be a maul that can't be used with strenght below 15, and a rapier that can't be used by units with strenght above 15.