Quick fix for gamemode loading all sounds from 'sound' folder instead of just 4.

- Added small workaround to prevent "melting" camera distortions bug.
- Added clientside convar 'slender_filmgrain 0/1' to switch between filmgrain or normal distortions. Clients with dx8 or lower will have filmgrain instead.
- Minor sound effects tweaks.
- Primary flashlight is less brighter now.

Hopefully fixed content not being downloaded to clients.