Snowfort V6

This update is just to match the version on the Steam Workshop, which finally fixes the broken ambient sounds.

Updated the map to match the version that is on the Workshop. Changes include:
-Added festive health/ammo pickups
-Further improved the transition between the water and the frozen pond
-Rearranged the snow on the frozen pond
-Added two small health packs on the frozen pond to compensate for the lack of fall damage protection that the water provided
-Added missing clip brushes and optimizations (whoops)
-Clipping improvements

I've renamed the map to "Snowfort" thanks to many suggestions. Also the transition from the sewer water to ice has been improved, and some bugs have been fixed.

The water under the bridge is now frozen. For now the water in the sewers is still liquid, that may or may not change. I also fixed some bugs and added some more snowy props.