Add a hook for fuel tank explosion
New armor properties tool
also restores the change to ductility
Prevent possible nil value error
Should fix #56
Fix engine mass ratio calculator
Wasn't detecting props parented to props
Fixes #51
Experimental change to HP rounds - comparable in penetration with AP rounds now.
Did some work on the new XCFMenu fuel panel.
Merge remote-tracking branch 'remotes/upstream/master'

Conflicts:
	lua/acf/server/sv_acfbase.lua
	lua/autorun/acf_globals.lua
	lua/weapons/gmod_tool/stools/acfarmorprop.lua