Sound improvements for DeadGuy

Adds and implements 4 new death sounds (generated by distorting noise
waves and square waves, then dropping the sample rate.)
Also includes a light impact sound for corpses hitting the ground.
Example: http://youtu.be/HQW0aJ5nUsI
Increased volume
Merge pull request #220 from MrRatermat/master

Sound additions for DeadGuy