TF2 SDK Update Sweep

● Enabled radial fog;
● Adjusted fog values outdoors.

● Added fade to leaf particle materials;
● Removed overlapping Xmas gift prop.

- fixed potential external vscript event incompatibility

- Fixed holiday events not occuring in pregame

RC4b:

- Fixed erroneous texture alignment on silos in skybox
- Adjusted holiday script events

RC4a:

- Performance improvements
- Fixed a bug in the script that would cause it to not check for duplicate statues outside of April 8
- Added Smissmas event