New Mech "Scarab"! Plus a bunch of mech fixes

Adds a new mech the "Scarab"! A fast scout mech with terrible armor and health and equipment slots, but it's fast! Ideal for enter a conflict, scouting, maybe taking a pot shot and and then BUGGERING off.
Bug fixes:
-Fixes Polecat armor to plasteel exploit and makes the polecat actually use up the armor.
-Fixes the Serenity eating entire stacks of plasteel and giving gygax armor plates when you try to get it back.
-Fixes the Phoron bore to HOPEFULLY show up in the mechfab in the server.

code/game/objects/items/weapons/circuitboards/mecha_ch.dm

@@ -0,0 +1,21 @@
+#ifdef T_BOARD_CHMecha
+#error T_BOARD_CHMECHA already defined elsewhere, we can't use it.
+#endif
+#define T_BOARD_CHMECHA(name)	"exosuit module circuit board (" + (name) + ")"
+//renaming CHmecha for Chomp mecha to allow for more to be made if needed.
+
+/obj/item/weapon/circuitboard/mecha/scarab
+		origin_tech = list(TECH_DATA = 4)
+
+/obj/item/weapon/circuitboard/mecha/scarab/peripherals
+		name = T_BOARD_CHMECHA("Scarab peripherals control")
+		icon_state = "mcontroller"
+
+/obj/item/weapon/circuitboard/mecha/scarab/targeting
+		name = T_BOARD_CHMECHA("Scarab weapon control and targeting")
+		icon_state = "mcontroller"
+		origin_tech = list(TECH_DATA = 4, TECH_COMBAT = 4)
+
+/obj/item/weapon/circuitboard/mecha/scarab/main
+		name = T_BOARD_CHMECHA("Scarab central control")
+		icon_state = "mainboard"