More self-help options on Expert Versus (L4D1)

Ok Expert versus seems a little bit to hard so we added some extra help for the survivors to balance things a bit more It's still BETA so please report any problems here.

When you have either pillz or a medkit you can:

- Revive yourself when incapped (Press and hold DUCK key for 3 seconds).
- Pickup pillz or medkit when you are incapped.
- Revive eachother when incapped, this means when 2 players are incapped they can help one another (no pillz/medkit needed).

Everything is controlled with the DUCK key (defaults to LEFT-CTRL). If it works good we might add it to other servers as well so we can increase infected strength once more