[mff_pclasses] Stop using asbolute stats values

- Stop using absolute stats values for stamina and manamax when you can
   add/subtract in on_assign and on_unassign
 - Use on_update for hunters to determine whether or not to add the
   sprint bonus from the full reinforced leather armor set

mods/mff/mff_pclasses/hunter.lua

@@ -6,28 +6,33 @@
 -- See https://github.com/Ombridride/minetest-minetestforfun-server/issues/114
 --
 
+local tmp = {}
+
 pclasses.api.register_class("hunter", {
 	on_assigned = function(pname, inform)
 		if inform then
 			minetest.chat_send_player(pname, "You are now a hunter")
 			minetest.sound_play("pclasses_full_hunter", {to_player=pname, gain=1})
 		end
+		sprint.increase_maxstamina(pname, 10)
 		minetest.log("action", "[PClasses] Player " .. pname .. " become a hunter")
 	end,
 	on_unassigned = function(pname)
-		sprint.set_default_maxstamina(pname)
+		sprint.decrease_maxstamina(pname, 10)
 	end,
 	on_update = function(pname)
-		local staminavalue = 30
-		local manavalue = 100
 		local reinforced = pclasses.api.util.does_wear_full_armor(pname, "reinforcedleather", true)
 		if reinforced then
-			staminavalue = staminavalue + 20
+			if not tmp[pname] then
+				tmp[pname] = true
+				sprint.increase_maxstamina(pname, 10) -- 10 more
+			end
 		else
-			staminavalue = staminavalue + 10
+			if tmp[pname] then
+				tmp[pname] = false
+				sprint.decrease_maxstamina(pname, 10)
+			end
 		end
-		sprint.set_maxstamina(pname, staminavalue)
-		mana.setmax(pname, manavalue)
 	end,
 	switch_params = {
 		color = {r = 30, g = 170, b = 00},