Overhaul global defines and vars

This commit overhauls the global.dm file, global_lists.dm file, and
defines.dm file into a tree system based on -tg-.

All defines have been split and distributed in code/__DEFINES/

Everything from global.dm and global_lists.dm has been split and
distributed in code/_globalvars

The _compile_options.dm file contains anything that absolutely, 100%, must
be initialized before world.dm.

Name definitions have been moved to code/_globalvars/lists/names.dm.

Other things to note
 - All instances of something.z == 2/1/3/5 have been replaced with easily
   configurable defines, labeled ZLEVEL_. The map include file can
   override these by defining custom ones in it's file, as it is at the
   top of the tree.

code/modules/computer3/computers/prisoner.dm

@@ -43,7 +43,7 @@
 				if(!T.implanted) continue
 				var/loc_display = "Unknown"
 				var/mob/living/carbon/M = T.imp_in
-				if(M.z == 1 && !istype(M.loc, /turf/space))
+				if(M.z == ZLEVEL_STATION && !istype(M.loc, /turf/space))
 					var/turf/mob_loc = get_turf(M)
 					loc_display = mob_loc.loc
 				if(T.malfunction)