General improvements, support Nightblade more accurately

- Added a display for current Elusive effect in the Calcs tab, under Movement Speed in Other Defences, which only shows up while Elusive.
- Much better support for Nightblade Support. Now gives Crit Multi and Base Crit Chance to attacks while using Claws or Daggers.
- Tweaked how I implemented Elusive Effect on gems. Now is implemented specifically for Claws/Daggers on Nightblade, and is added as a global Skill Mod for Withering Step and any future gems which give the stat.
- Are you Elusive? button works and shows up more consistently.

Modules/ModParser-3_0.lua

@@ -832,6 +832,8 @@ local modTagList = {
 	["while you have onslaught"] = { tag = { type = "Condition", var = "Onslaught" } },
 	["while phasing"] = { tag = { type = "Condition", var = "Phasing" } },
 	["while you have tailwind"] = { tag = { type = "Condition", var = "Tailwind" } },
+	["while elusive"] = { tag = { type = "Condition", var = "Elusive" } },
+	["gain elusive"] = { tag = { type = "Condition", varList = { "CanBeElusive", "Elusive" } } },
 	["while you have arcane surge"] = { tag = { type = "Condition", var = "AffectedByArcaneSurge" } },
 	["while you have cat's stealth"] = { tag = { type = "Condition", var = "AffectedByCat'sStealth" } },
 	["while you have avian's might"] = { tag = { type = "Condition", var = "AffectedByAvian'sMight" } },
@@ -1164,6 +1166,10 @@ local specialModList = {
 		mod("NonChaosDamageGainAsChaos", "BASE", num, { type = "Condition", var = "KilledRecently" }, { type = "Multiplier", var = "CurseOnEnemy" }), 
 	} end,
 	["cannot be stunned while you have energy shield"] = { mod("AvoidStun", "BASE", 100, { type = "Condition", var = "HaveEnergyShield" }) },
+--	["inflict withered"] = {
+--		flag("Condition:CanWither"),
+--		mod("Dummy", "DUMMY", 1, 0, 0, { type = "Condition", var = "CanWither" })
+--	},
 	-- Pathfinder
 	["always poison on hit while using a flask"] = { mod("PoisonChance", "BASE", 100, { type = "Condition", var = "UsingFlask" }) },
 	["poisons you inflict during any flask effect have (%d+)%% chance to deal (%d+)%% more damage"] = function(num, _, more) return { mod("Damage", "MORE", tonumber(more) * num / 100, nil, 0, KeywordFlag.Poison, { type = "Condition", var = "UsingFlask" }) } end,