Fixes rad suits not completely protecting against radiation

* The calculation of human armor values for full-body effects is now weighted by body part. The fact that it was unweighted was an issue before as it meant that not having hand or feet protection reduced the player's protection from full body effects much more than it should have, while not having your hands protected was just as bad as not having your chest protected.

* Adds HANDS and FEET coverage to radsuits to allow them to provide complete radiation protection, as they did before. It would probably be better to either update the radsuit sprite to reflect the additional coverage (make the sprite appear to cover the hands and feet the same way hardsuits do), or to add radiation proof gloves and boots as part of the radiation suit set (which would be potentially problematic for taj and unathi engineers). Alternatively we could make radiation suits cover the feet but supply radiation suit gloves.