Chem reaction cleanup

Reorganizes handle_reactions() in preparation for implementing
reactions-over-time.
Moves chemistry initializations into global_init.

code/world.dm

@@ -1,3 +1,14 @@
+
+/*
+	The initialization of the game happens roughly like this:
+	
+	1. All global variables are initialized (including the global_init instance).
+	2. The map is initialized, and map objects are created.
+	3. world/New() runs, creating the process scheduler (and the old master controller) and spawning their setup.
+	4. processScheduler/setup() runs, creating all the processes. game_controller/setup() runs, calling initialize() on all movable atoms in the world.
+	5. The gameticker is created.
+
+*/
 var/global/datum/global_init/init = new ()
 
 /*
@@ -7,8 +18,11 @@ var/global/datum/global_init/init = new ()
 
 	makeDatumRefLists()
 	load_configuration()
+	
+	initialize_chemical_reagents()
+	initialize_chemical_reactions()
 
-	qdel(src)
+	qdel(src) //we're done
 
 
 /world