Engines and gearboxes can now be weld parented

- also fixed gearboxes not being checked for legality when linked to other
  gearboxes
- removed some leftover files with unused code. closes #70
Added bullet UID system to lower net traffic.
Rebalanced ACF SWEPs.
Added ACF LMG.
Modified rocket functions to gain more accurate conversions.
Small modification to ammo panel to spew formatted ammo data while debug is active.
Merge remote-tracking branch 'remotes/upstream/master'

Conflicts:
	lua/autorun/acf_globals.lua
	lua/entities/acf_rack/cl_init.lua
	lua/entities/acf_rack/init.lua
	lua/entities/acf_rack/shared.lua