Horror Form Lings! [Unfinished] [Needs Testing]

# Horror Form mob, subtype of Carbon:
- Power to Become a Horror Form (No reverse power, the normal humanform power works already)
- Horror Forms can rip open Doors, This functions the same as any mob that can open doors EXCEPT Horror forms can open powered doors, but with a longer delay
- Horror Forms can smash walls, This functions the same as the Hulk wall smash (based on wall strength)
- Horror Forms can sacrifice one of their DNA to form an 'Assimilant' A weak, power restricted changeling
- An Assimilant is not formed, and the ling is not Charged if their are no Clients to accept an Assimilant
- Assimilants ask ghosts to command them
- Horror Form lings have hands, this needs further tests

# Head spiders, subtype of simple_animal:
- Head spiders can kick client's out of their mob, this is UNTESTED IN MULTIPLAYER
- Head spiders removing clients from mobs is for all /carbon, ALIENS HAVE NOT YET BEEN PROTECTED
- Head spiders form from a dead Horror Form ling
- Head spiders are controlled by the Dead Ling itself

# TODO:
- Run some balance checks
- PROTECT ALIENS FROM HEAD SPIDERS
- Add 1-2 more Unique Powers to Horror Forms
- Test Horror Form ling's hands interacting with Items
- No doubt some things I have forgotten
- Remove Commented code, Some of it is bad, some of it is just for Debug (Client stuff etc.)


This is a bit early, but this is the first build where major issues have not reared their head, so I symbolised that with a Commit and a PR.

# Thread/Poll is here:
http://www.ss13.eu/phpbb/viewtopic.php?f=48&t=4361
(Current Poll is 23 for Yes, and that's all she wrote)

Yes I am going to be an uncaring mother to this PR, but that's because I'm working on the code!