As noted in issue #1501, the dragCoefficient property was misspelled in multiple locations as "dragCoeffiecient"
This corrects the spelling in all of those locations.
This reduces duplication by grouping assets used by multiple weapons in one location: shared.
This reduces duplication and cleans particle fx that was spread across multiple files. We now have rocketfx.cs and grenadefx.cs
This also fixes some minor particle fx console warnings/errors.
Fixed missing material for Cheetah Turret.