moved shield files to folder, made circuitry for shielding gens/caps researchable, various tweaks and balances to the research requirements, made shield gens/capacitors orderable via cargo

Signed-off-by: Cael_Aislinn <cael_aislinn@yahoo.com.au>

code/WorkInProgress/Cael_Aislinn/ShieldGen/energy_field.dm

@@ -0,0 +1,52 @@
+
+//---------- actual energy field
+
+/obj/effect/energy_field
+	name = "energy field"
+	desc = "Impenetrable field of energy, capable of blocking anything as long as it's active."
+	icon = 'shielding.dmi'
+	icon_state = "shieldsparkles"
+	anchored = 1
+	layer = 2.1
+	density = 0
+	invisibility = 2
+	var/strength = 0
+	var/obj/machinery/shield_gen/parent
+	var/stress = 0
+
+/obj/effect/energy_field/ex_act(var/severity)
+	Stress(0.5 + severity)
+
+/obj/effect/energy_field/bullet_act(var/obj/item/projectile/Proj)
+	Stress(1 + 1 * (Proj.damage / 100))
+
+
+/obj/effect/energy_field/meteorhit(obj/effect/meteor/M as obj)
+	if(M)
+		walk(M,0)
+
+/obj/effect/energy_field/proc/Stress(var/severity)
+	strength -= severity
+	stress += severity
+
+	//if we take too much damage, drop out - the generator will bring us back up if we have enough power
+	if(strength < 1)
+		invisibility = 2
+		density = 0
+
+/obj/effect/energy_field/proc/Strengthen(var/severity)
+	strength += severity
+
+	//if we take too much damage, drop out - the generator will bring us back up if we have enough power
+	if(strength > 1)
+		invisibility = 0
+		density = 1
+
+/obj/effect/energy_field/CanPass(atom/movable/mover, turf/target, height=1.5, air_group = 0)
+	//Purpose: Determines if the object (or airflow) can pass this atom.
+	//Called by: Movement, airflow.
+	//Inputs: The moving atom (optional), target turf, "height" and air group
+	//Outputs: Boolean if can pass.
+
+	//return (!density || !height || air_group)
+	return density