get sound by depth
add ambient sound effects to battlescape

defined by terrain type.
adjust bubbles when aiming.
use different sprite sheet for underwater bullets
fix reorder, remove unused variables from Globe
Merge pull request #939 from ajschult/Globe-compile

fix reorder, remove unused variables from Globe
weapons that don't work on land
else*
Added xBRZ scaler.
Some more GLSL shaders for good measure.
Fix.
Fixx
Fixxx