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/src/nodebuilder.h

@@ -0,0 +1,70 @@
+#ifndef NODE_NODEBUILDER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+#define NODE_NODEBUILDER_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 <vector>
+
+#include "yaml-cpp/anchor.h"
+#include "yaml-cpp/emitterstyle.h"
+#include "yaml-cpp/eventhandler.h"
+#include "yaml-cpp/node/ptr.h"
+
+namespace YAML {
+namespace detail {
+class node;
+}  // namespace detail
+struct Mark;
+}  // namespace YAML
+
+namespace YAML {
+class Node;
+
+class NodeBuilder : public EventHandler {
+ public:
+  NodeBuilder();
+  virtual ~NodeBuilder();
+
+  Node Root();
+
+  virtual void OnDocumentStart(const Mark& mark);
+  virtual void OnDocumentEnd();
+
+  virtual void OnNull(const Mark& mark, anchor_t anchor);
+  virtual void OnAlias(const Mark& mark, anchor_t anchor);
+  virtual void OnScalar(const Mark& mark, const std::string& tag,
+                        anchor_t anchor, const std::string& value);
+
+  virtual void OnSequenceStart(const Mark& mark, const std::string& tag,
+                               anchor_t anchor, EmitterStyle::value style);
+  virtual void OnSequenceEnd();
+
+  virtual void OnMapStart(const Mark& mark, const std::string& tag,
+                          anchor_t anchor, EmitterStyle::value style);
+  virtual void OnMapEnd();
+
+ private:
+  detail::node& Push(const Mark& mark, anchor_t anchor);
+  void Push(detail::node& node);
+  void Pop();
+  void RegisterAnchor(anchor_t anchor, detail::node& node);
+
+ private:
+  detail::shared_memory_holder m_pMemory;
+  detail::node* m_pRoot;
+
+  typedef std::vector<detail::node*> Nodes;
+  Nodes m_stack;
+  Nodes m_anchors;
+
+  typedef std::pair<detail::node*, bool> PushedKey;
+  std::vector<PushedKey> m_keys;
+  std::size_t m_mapDepth;
+};
+}
+
+#endif  // NODE_NODEBUILDER_H_62B23520_7C8E_11DE_8A39_0800200C9A66