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.

scripting/lua/api/events/BattleEvents.cpp

@@ -0,0 +1,67 @@
+/*
+ * BattleEvents.cpp, part of VCMI engine
+ *
+ * Authors: listed in file AUTHORS in main folder
+ *
+ * License: GNU General Public License v2.0 or later
+ * Full text of license available in license.txt file, in main folder
+ *
+ */
+#include "StdInc.h"
+
+#include "BattleEvents.h"
+
+#include "../../LuaStack.h"
+#include "../../LuaCallWrapper.h"
+#include "../Registry.h"
+#include "../../../../lib/battle/Unit.h"
+#include "SubscriptionRegistryProxy.h"
+
+namespace scripting
+{
+namespace api
+{
+namespace events
+{
+using ::events::ApplyDamage;
+
+VCMI_REGISTER_SCRIPT_API(ApplyDamageProxy, "events.ApplyDamage");
+
+const std::vector<ApplyDamageProxy::RegType> ApplyDamageProxy::REGISTER =
+{
+	{
+		"getInitalDamage",
+		LuaCallWrapper<ApplyDamage>::createFunctor(&ApplyDamage::getInitalDamage)
+	},
+	{
+		"getDamage",
+		LuaCallWrapper<ApplyDamage>::createFunctor(&ApplyDamage::getDamage)
+	},
+	{
+		"setDamage",
+		LuaCallWrapper<ApplyDamage>::createFunctor(&ApplyDamage::setDamage)
+	},
+	{
+		"getTarget",
+		LuaCallWrapper<ApplyDamage>::createFunctor(&ApplyDamage::getTarget)
+	}
+};
+
+const std::vector<ApplyDamageProxy::CustomRegType> ApplyDamageProxy::REGISTER_CUSTOM =
+{
+	{
+		"subscribeBefore",
+		&SubscriptionRegistryProxy<ApplyDamageProxy>::subscribeBefore,
+		true
+	},
+	{
+		"subscribeAfter",
+		&SubscriptionRegistryProxy<ApplyDamageProxy>::subscribeAfter,
+		true
+	}
+};
+
+}
+}
+}
+