Attack proc removal/refactor.

- Removes attack_slime, attack_paw and attack_animal entirely.
- Moves the mob-specific behavior of the previous procs onto UnarmedAttack and moves the rest into an atom/attack_generic proc.
- Because of this, carbon/alien can now eat food. Yay.
- Adds IsAdvancedToolUser() checks to the attack_hand procs previously bypassed in favour of attack_paw.
- Adds typechecks to mob attack_hand calls to prevent runtiming due to monkeys not having the same vars.
- Removes deprecated stunglove code from several attack_hand definitions.
- Also does some cosmetic stuff, changes emote to custom_emote in a few places, changes all the simple_animal attack strings to past tense to match 'x has punched y'.