Fixes #2326

- Moves Robotic repair stuff to the two item's respected attack()'s
- Removed them from the human_defense.dm
Moves some use()'s so that they always execute the message near them.
Adds item_heal_robotic() - a way for items to trigger robotic limb heal procs without copy-paste
Merge pull request #2373 from RobRichards1997/14/01/2014-Bug-Fixes

Robotic Repair Missing fixes [Fixes #2326]