Instagib: Badlands

Instagib: Badlands a2

+added menu photos
+added mission briefing
+added new sound for melee kills
+added new spawn point

|adjusted clipping to fix various unintended perch points
|adjusted clipping on roofs
|made various props nonsolid

-removed some clipping in a few roofs
-removed unnecessary ammo boxes
-removed minecarts near spiral for easier movement over the wooden structure