Thermite Effectiveness Scaling with Volume

-The more thermite is applied to a wall, the faster it will burn
-Scales between approx 10-25 seconds
-Rwalls have a higher minimum threshold and burn time
-Applying thermite to a wall now leaves a visible stain on the wall
Added a SFX to igniting thermite
Thermiting walls leave admin prints
Merge pull request #500 from Ikarrus/thermitescale

Thermite Effectiveness Scaling with Volume and Wall Type