Fixes for a IPC potato men things.

Fixed IPCs magically healing their hands by swapping their hands out.
Added Robot Hands, Feet and Groin.
Added Robo hands feet and groin to the Mech Fab.
Made legless IPCs fall-over when taking off their leg.
Small updates to previous code.

Updated Changelog.
Added Robo Pelvis to Mech-fabs.
Made Hands and Feet fit in boxes.
Made IPCs not care about dismembered limbs.
Fixed visual error.

Made it so that clicking a limb into place didn't keep showing that limb
in your hand.
Merge pull request #185 from TehFlaminTaco/master

Updates that fix a fair bit of the Potato men code.