Update to medical items and death code

Almost all medical items changed:

Bandages will only stop bleeding now, no health gain.
Medkits won't give health either, they will stop bleeding and have
painkiller effects.
Adrenaline Injector is now the only way to revive a knocked out player,
a quick jab instead of a long CPR animation.
Doctors bag gives 50 health points instead of 70.

Knocked out players can still be treated with bandages/medkits/docbags.
These items just won't revive the player any more.

Fixed a bug with the taser stopping a player from bleeding.

Shifted a lot of death related code to the death script and used hooks
where appropriate.

Fixed syntax parameter typos from the update to Drugs.pwn.

Fixed a bug where exiting a locked vehicle will leave it locked (and
thus the player locked out)

Fixed a bug where newly created defences would show -1 as their
hitpoints.

Fixed some syntax parameter typos with the CreateButton lines in
CreateDefence