Multi Stage Carcosa stage3_a2

STAGE 3 UPDATED TO A2

EXPERIMENTAL: Added a door between A and B at the staircase that opens once A is captured
I've added this access so that players who take the staircase can go to B this way now instead of going back. I have no idea how this is gonna play out, hopefully it doesn't suck.

- Added a couple of crates near A to reduce sightline into and from the BLU spawn area
- Added func_nobuild on the crates and barrels at B -- this should make sentry nests less ridiculous
- Added func_nobuild on the control point at B -- this should make sentry nests less ridiculous
- Added playerclip in the Gates 1/2 area
- Added a bit more playerclip at different points in the map
- Extended BLU gates func_doors to fill the frames
- Moved BLU resupply locker a bit closer to the door
- Slightly moved one metal cover at B to prevent players from bumping into it

Here's how it looks: