Added super cool weapon pack.

Very nice pack with animations, sounds, particle systems, projectiles,
pickups and super cool models.

1) The main character and the enemies now use a rifle weapon (Other
weapon usage is to be implemented).
2) Fixed the spawn location for the projectiles. The location is the
location of the muzzle socket of the weapons. However, if there isn't
any weapon attached to the character, he is using an alternative spawn
location.