Boxers: cull inaccessible areas

[sprunk]

Some maps have the startbox extend out of the play area (eg. trojan hills):

• misclicking can screw you up
• trolls can start in the corner and rush a cloaker or something (think the SC2 command center liftoff at start thing). This makes for a very unfun match for the opponent as either they get very confused or, if they know what's going on, a boring task of finding and bombing all the stuff. This is somewhat hard to fix through the boxes alone because recon comm has jump right from level 0 which ruins everything.

[Arch-Shaman]

Maps found so far:

• [ ] Bandit plains
• [ ] Cold snap 2
• [ ] The Rock Jungle
• [ ] Titan
• [ ] Saltscape
• [ ] Tundra
• [ ] Tropical v2
• [ ] Trojan Hills
• [ ] Tundra?
• [ ] Turmult?
• [ ] Stronghold beta (Marked for FFA, has boxes for 2 teams only)