Cleaning up machine process()s

But first! Unrelated to process():
- Only humans and monkeys can move into sleepers.
- Immovable rods no longer delete themselves if they hit a shuttle. Instead they act as if the shuttle doesn't exist. This should help cut down on rods deleting themselves before going through the station.

And now back to our regularly scheduled programming...

Removed process() that were doing nothing from:
- Dispenser(the one that dispenses O2 and Plasma tanks)
- Robotic Fabricators
- Crew Monitoring computer

Reworked hydroponic's process(). 
- Merged if statements together since most of them lacked "else if"s or were duplicate checks.
- Changed a while loop into a for loop as sloppy coding or an admin var-editing could cause an infinite loop.

Removed a sleep(100) { process() } from the operating table's constructor as the MC will call process() regardless.

Cleaned up shieldgen.dm
- Changed a while loop into an if statement. The loop was unnecessary
- Moved some stuff around so it's not nearly as confusing.
- Standardized the proc and variable definitions.
- These are not currently in-game but they are amazing items. I'll see about sorting out their bugs and getting them in proper working order.

Removed a for(var in world) from
- cleanbot process()
- floorbot process()

Removed computer/engine/process() from robot/computer code
- /obj/machinery/computer/engine does not exist in the first place...

Note: These are only some of the machinery process()s. I didn't want to potentially break too much at once. More to come.

git-svn-id: http://tgstation13.googlecode.com/svn/trunk@4017 316c924e-a436-60f5-8080-3fe189b3f50e

code/game/machinery/computer/robot.dm

@@ -97,12 +97,13 @@
 	onclose(user, "computer")
 	return
 
-/obj/machinery/computer/engine/process()
+//Why is this in robot/computer and why does it exist when /obj/machinery/computer/engine does not? -Nodrak
+/*/obj/machinery/computer/engine/process()
 	if(stat & (NOPOWER|BROKEN))
 		return
 	use_power(500)
 	src.updateDialog()
-	return
+	return*/
 
 /obj/machinery/computer/robotics/Topic(href, href_list)
 	if(..())