Updated workshop icon

Beta version 6
* Put up some windows on all floors of the train station building
* Add doors to new cinema (separates from rest of map using areaportal when closed)
* Made roads mostly level with flatgrass area (this should mostly fix the eyesore "z-fighting" with the roads)
* Fixed hole in slope at northwest corner of map
* Painted nodraw surfaces on sides of some brushes
* Made most of the markings on the airport runway bruhes part of the ground rather than overlays (also fixes the z-fighting there)
* Started adding some roads to skybox
* Opened up road tunnel underneath airport in preparation for highway entrance there
* Completed one way loop of highway
* Added highway exit
* Moved entrance to second subway station as to not make it intersect with highway slope
* Added some walls around highway tunnel entrances
* Adjusted HDR bloom to make it less ridiculously bright
* Made the skybox paintable, like gm_flatgrass
* Changed some textures of sidewalks to make them more consistent
* Fixed bumpy highway curve collision model
* Fixed broken cubemaps
* Some optimization
* Other minor changes

None Provided

Initial addon creation.