Migrate core source files to C++. Add yaml-cpp project as dependency (#2207)

By updating to this commit, Linux users have to regenerate Makefiles by re-running the configure script.

* Added yaml-cpp project as a 3rdparty library
* Migrated source files core to C++
* Updated configure scripts
* Make Linux installations compile *.cpp files
* Made server components' main source file C++
* Also made headers CPP-aware.

* Added basic C wrapper for yaml-cpp library
* YAML-node path is delimited by periods.
* Basic integer types and string are supported.
* Strings returned from this wrapper have to be freed with malloc.h::aFree
* Arrays (sequence) is supported with iterator wrapper.
* Remember to free every wrapper you create!

* Add yaml-cpp as dependency of common project
* Made the repo not ignore *.yml files

Thanks to @aleos89 and @Lemongrass3110.

3rdparty/yaml-cpp/include/yaml-cpp/parser.h

@@ -0,0 +1,86 @@
+#ifndef PARSER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+#define PARSER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+
+#if defined(_MSC_VER) ||                                            \
+    (defined(__GNUC__) && (__GNUC__ == 3 && __GNUC_MINOR__ >= 4) || \
+     (__GNUC__ >= 4))  // GCC supports "pragma once" correctly since 3.4
+#pragma once
+#endif
+
+#include <ios>
+#include <memory>
+
+#include "yaml-cpp/dll.h"
+#include "yaml-cpp/noncopyable.h"
+
+namespace YAML {
+class EventHandler;
+class Node;
+class Scanner;
+struct Directives;
+struct Token;
+
+/**
+ * A parser turns a stream of bytes into one stream of "events" per YAML
+ * document in the input stream.
+ */
+class YAML_CPP_API Parser : private noncopyable {
+ public:
+  /** Constructs an empty parser (with no input. */
+  Parser();
+
+  /**
+   * Constructs a parser from the given input stream. The input stream must
+   * live as long as the parser.
+   */
+  explicit Parser(std::istream& in);
+
+  ~Parser();
+
+  /** Evaluates to true if the parser has some valid input to be read. */
+  explicit operator bool() const;
+
+  /**
+   * Resets the parser with the given input stream. Any existing state is
+   * erased.
+   */
+  void Load(std::istream& in);
+
+  /**
+   * Handles the next document by calling events on the {@code eventHandler}.
+   *
+   * @throw a ParserException on error.
+   * @return false if there are no more documents
+   */
+  bool HandleNextDocument(EventHandler& eventHandler);
+
+  void PrintTokens(std::ostream& out);
+
+ private:
+  /**
+   * Reads any directives that are next in the queue, setting the internal
+   * {@code m_pDirectives} state.
+   */
+  void ParseDirectives();
+
+  void HandleDirective(const Token& token);
+
+  /**
+   * Handles a "YAML" directive, which should be of the form 'major.minor' (like
+   * a version number).
+   */
+  void HandleYamlDirective(const Token& token);
+
+  /**
+   * Handles a "TAG" directive, which should be of the form 'handle prefix',
+   * where 'handle' is converted to 'prefix' in the file.
+   */
+  void HandleTagDirective(const Token& token);
+
+ private:
+  std::unique_ptr<Scanner> m_pScanner;
+  std::unique_ptr<Directives> m_pDirectives;
+};
+}
+
+#endif  // PARSER_H_62B23520_7C8E_11DE_8A39_0800200C9A66