Extraction

Past 72hr Jam Entry Extraction b6

* fixed the flag being permanently neutral (whoops)
Gamemode:
* disabled shot clock mode on the flag
* fixed several cases where the helicopter would show up when it shouldn't/wouldn't show up when it should
* clipped stairs

Helicopter Pad:
* added some buildings on either side of the helipad, as well as routes onto the helipad

Flag Zone:
* added an upper area behind the flag which I imagine will be used for sentry nests
* accidentally fixed the rendering bug near the lower tunnel

Mid:
* added a bit more health to the lower areas
* lowered the radio-tower building a bit

Spawn:
* fixed a spawn door on BLU side opening for both teams