Entities redesign and a few ERM features

* Made most Handlers derived from CHandlerBase and moved service API there.
* Declared existing Entity APIs.
* Added basic script context caching
* Started Lua script module
* Started Lua spell effect API
* Started script state persistence
* Started battle info callback binding
* CommitPackage removed
* Extracted spells::Caster to own header; Expanded Spell API.
* implemented !!MC:S, !!FU:E, !!FU:P, !!MA, !!VR:H, !!VR:C
* !!BU:C, !!BU:E, !!BU:G, !!BU:M implemented
* Allow use of "MC:S@varName@" to declare normal variable (technically v-variable with string key)
* Re-enabled VERM macros.
* !?GM0 added
* !?TM implemented
* Added !!MF:N
* Started !?OB, !!BM, !!HE, !!OW, !!UN
* Added basic support of w-variables
* Added support for ERM indirect variables
* Made !?FU regular trigger
* !!re (ERA loop receiver) implemented
* Fixed ERM receivers with zero args.

scripts/lib/erm/FU_T.lua

@@ -0,0 +1,15 @@
+local TriggerBase = require("core:erm.TriggerBase")
+local _
+
+local FU = TriggerBase:new()
+
+function FU:call(p1, x)
+	self.ERM.activeEvent = nil
+	self.ERM.activeTrigger = self
+	for _, fn in ipairs(self.fn) do
+		fn(self.e, self.y, x)
+	end
+	self.ERM.activeTrigger = nil
+end
+
+return FU