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/modules/research/designs/circuits/circuits_ch.dm

@@ -4,3 +4,24 @@
 	req_tech = list(TECH_DATA = 5, TECH_ENGINEERING = 5, TECH_BLUESPACE = 4)
 	build_path = /obj/item/weapon/circuitboard/microwave/advanced
 	sort_string = "MAAAC"
+
+/datum/design/circuit/mecha/scarab_main
+	name = "'Scarab' central control"
+	id = "scarab_main"
+	req_tech = list(TECH_DATA = 4)
+	build_path = /obj/item/weapon/circuitboard/mecha/scarab/main
+	sort_string = "SAAAA"
+
+/datum/design/circuit/mecha/scarab_peri
+	name = "'scarab' peripherals control"
+	id = "scarab_peri"
+	req_tech = list(TECH_DATA = 4)
+	build_path = /obj/item/weapon/circuitboard/mecha/scarab/peripherals
+	sort_string = "SAAAB"
+
+/datum/design/circuit/mecha/scarab_targ
+	name = "'Scarab' weapon control and targeting"
+	id = "scarab_targ"
+	req_tech = list(TECH_DATA = 4, TECH_COMBAT = 2)
+	build_path = /obj/item/weapon/circuitboard/mecha/scarab/targeting
+	sort_string = "SAAAC"

code/modules/research/mechfab_designs_ch.dm

@@ -1,18 +1,59 @@
-
-/datum/design/item/mecha
-	build_type = MECHFAB
-	category = "Exosuit Equipment"
-	time = 10
-	materials = list(DEFAULT_WALL_MATERIAL = 7500)
-
-/datum/design/item/mecha/AssembleDesignDesc()
-	if(!desc)
-		desc = "Allows for the construction of \a '[item_name]' exosuit module."
-
 /datum/design/item/mecha/phoron_bore
 	name = "PB-23 \"Phobos\" Phoron Bore"
-	desc = "A large, mecha-mounted Phoron bore. It makes use a specialized compressed phoron crystal. The bolt it fires travels for 6 tiles before disapaiting, breaking rocks and extracting minerals."
+	category = "Exosuit Equipment"
 	id ="mech_phoron_bore"
 	req_tech = list(TECH_POWER = 5, TECH_PHORON = 5, TECH_MATERIAL = 5)
 	materials = list(MAT_PLASTEEL = 4000, "phoron" = 10000, "silver" = 2000)
-	build_path =/obj/item/mecha_parts/mecha_equipment/weapon/phoron_bore
+	build_path =/obj/item/mecha_parts/mecha_equipment/weapon/phoron_bore
+
+/datum/design/item/mechfab/scarab
+	category = "Scarab"
+
+/datum/design/item/mechfab/scarab/chassis
+	name = "Scarab Chassis"
+	id = "scarab_chassis"
+	build_path = /obj/item/mecha_parts/chassis/scarab
+	time = 10
+	materials = list(DEFAULT_WALL_MATERIAL = 15000)
+
+/datum/design/item/mechfab/scarab/torso
+	name = "Scarab Torso"
+	id = "scarab_torso"
+	build_path = /obj/item/mecha_parts/part/scarab_torso
+	time = 30
+	materials = list(DEFAULT_WALL_MATERIAL = 30000, "glass" = 10000)
+
+/datum/design/item/mechfab/scarab/head
+	name = "Scarab Head"
+	id = "scarab_head"
+	build_path = /obj/item/mecha_parts/part/scarab_head
+	time = 20
+	materials = list(DEFAULT_WALL_MATERIAL = 12500, "glass" = 5000)
+
+/datum/design/item/mechfab/scarab/left_arm
+	name = "Scarab Left Arm"
+	id = "scarab_left_arm"
+	build_path = /obj/item/mecha_parts/part/scarab_left_arm
+	time = 20
+	materials = list(DEFAULT_WALL_MATERIAL = 10000)
+
+/datum/design/item/mechfab/scarab/right_arm
+	name = "Scarab Right Arm"
+	id = "scarab_right_arm"
+	build_path = /obj/item/mecha_parts/part/scarab_right_arm
+	time = 20
+	materials = list(DEFAULT_WALL_MATERIAL = 10000)
+
+/datum/design/item/mechfab/scarab/left_leg
+	name = "Scarab Left Legs"
+	id = "scarab_left_legs"
+	build_path = /obj/item/mecha_parts/part/scarab_left_legs
+	time = 20
+	materials = list(DEFAULT_WALL_MATERIAL = 30000)
+
+/datum/design/item/mechfab/scarab/right_leg
+	name = "Scarab Right Legs"
+	id = "scarab_right_legs"
+	build_path = /obj/item/mecha_parts/part/scarab_right_legs
+	time = 20
+	materials = list(DEFAULT_WALL_MATERIAL = 30000)