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.lua

@@ -0,0 +1,44 @@
+local ReceiverBase = require("core:erm.ReceiverBase")
+
+local FU = ReceiverBase:new()
+
+function FU:new(ERM, fun)
+	assert(fun, "!!FU requires 1 argument")
+	return ReceiverBase.new(self,
+	{
+		ERM=ERM,
+		fun=fun,
+	})
+end
+
+
+function FU:P(x, ...)
+	local argc = select('#', ...)
+	local newx = {}
+	local ret = {}
+
+	for idx = 1, argc do
+		local v = (select(idx, ...))
+		idx = tostring(idx)
+
+		if v ~= nil then
+			newx[idx] = v
+		end
+	end
+
+	self.ERM:callFunction(self.fun, newx)
+
+	for idx = 1, argc do
+		local v = (select(idx, ...))
+		if v == nil then
+			ret[idx] = newx[tostring(idx)]
+		else
+			ret[idx] = nil
+		end
+	end
+
+	return unpack(ret)
+end
+
+
+return FU