Carry weight rebalance

This nerfs the player's carry weight down to a more realistic number. New default is 100 lbs for a STR 8 character, with the minimum dropping to as low as 30 pounds at STR 0. Data was obtained through checking weights for army rucksack runs and a bit of experimentation with my own flimsy arms and a set of weights. Characters may carry up to 4 times that maximum limit, but once they pass 2 times their body begins to "strain under the weight", which can cause damage to the legs, torso, and arms, the chance of which increases as the amount they carry approaches 4x their normal maximum.

This also adds a new option, "Dangerous Pickups", which when enabled means the game will still add objects that are unloaded, or spawned from your action (such as shell casings or crafting) into your inventory even if this would cause you to be beyond the strain limit. This option is false by default.

Lastly this cleans up a lot of duplicate code that was checking if a player could pick something up and replaced it with the already existing functions.