Add mapping units/beacons for explo

code/modules/holomap/mapper.dm

@@ -1,6 +1,9 @@
 /obj/item/device/mapping_unit
 	name = "mapping unit"
 	desc = "A portable mapping unit, capable of locating other similar units on a map. Also has a short-range sonar mapping system."
+	description_info = "Use the device in your hand to add the mapping HUD to your screen. You can then power it on and change mapping modes.\
+	<br>The device will show other powered-on mapping units on the map, as well as activated mapping beacons, but only of the same 'type' mapping unit.\
+	<br>Normal mapping units can only display other normal beacons and mapping units, ERT mapping units can display other ERT, etc."
 	icon_state = "mapping_unit"
 	item_state = null
 	w_class = ITEMSIZE_SMALL

code/modules/mining/ore_redemption_machine/survey_vendor.dm

@@ -27,6 +27,8 @@
 		new /datum/data/mining_equipment("Titanium Fishing Rod",		/obj/item/weapon/material/fishing_rod/modern,						50),
 		new /datum/data/mining_equipment("Direct Payment - 1000",		/obj/item/weapon/spacecash/c1000,									500),
 		new /datum/data/mining_equipment("Industrial Equipment - Phoron Bore",	/obj/item/weapon/gun/magnetic/matfed/phoronbore/loaded,		500),
+		new /datum/data/mining_equipment("Survey Tools - Mapping Unit",	/obj/item/device/mapping_unit,										150),
+		new /datum/data/mining_equipment("Survey Tools - Mapping Beacon",/obj/item/device/holomap_beacon,									25),
 		new /datum/data/mining_equipment("Survey Tools - Shovel",		/obj/item/weapon/shovel,											20),
 		new /datum/data/mining_equipment("Survey Tools - Mechanical Trap",	/obj/item/weapon/beartrap,										30),
 		new /datum/data/mining_equipment("Digital Tablet - Standard",	/obj/item/modular_computer/tablet/preset/custom_loadout/standard,	100),