Large changeset, first part of editing H3 objects via mods feature. Changes:

- loading of all objects (including H3 objects) will be directed by mod handlers
- common base for all handlers accessible from mod system (IHanderBase)
- json format changes: use struct with string ID's instead of vector

- fixed some gcc/clang errors and warnings
- fixed several cases of memory leaks and invalid memory access (mostly related to usage of bonus system and/or identifiers resolution)

Note that right now loading is much slower than before due to excessive json validation (or not fast enough validator)

lib/IHandlerBase.h

@@ -0,0 +1,40 @@
+#pragma once
+
+/*
+ * IHandlerBase.h, 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
+ *
+ */
+
+class JsonNode;
+
+/// base class for all handlers that can be accessed from mod system
+class DLL_LINKAGE IHandlerBase
+{
+	// there also should be private member with such signature:
+	// Object * loadFromJson(const JsonNode & json);
+	// where Object is type of data loaded by handler
+	// primary used in loadObject methods
+
+public:
+	/// loads all original game data in vector of json nodes
+	/// dataSize - is number of items that must be loaded (normally - constant from GameConstants)
+	virtual std::vector<JsonNode> loadLegacyData(size_t dataSize) = 0;
+
+	/// loads single object into game. Scope is namespace of this object, same as name of source mod
+	virtual void loadObject(std::string scope, std::string name, const JsonNode & data) = 0;
+	virtual void loadObject(std::string scope, std::string name, const JsonNode & data, size_t index) = 0;
+
+	/**
+	 * Gets a list of objects that are allowed by default on maps
+	 *
+	 * @return a list of allowed objects, the index is the object id
+	 */
+	virtual std::vector<bool> getDefaultAllowed() const = 0;
+
+	virtual ~IHandlerBase(){}
+};