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/ostream_wrapper.cpp

@@ -0,0 +1,57 @@
+#include "yaml-cpp/ostream_wrapper.h"
+
+#include <algorithm>
+#include <cstring>
+#include <iostream>
+
+namespace YAML {
+ostream_wrapper::ostream_wrapper()
+    : m_buffer(1, '\0'),
+      m_pStream(0),
+      m_pos(0),
+      m_row(0),
+      m_col(0),
+      m_comment(false) {}
+
+ostream_wrapper::ostream_wrapper(std::ostream& stream)
+    : m_pStream(&stream), m_pos(0), m_row(0), m_col(0), m_comment(false) {}
+
+ostream_wrapper::~ostream_wrapper() {}
+
+void ostream_wrapper::write(const std::string& str) {
+  if (m_pStream) {
+    m_pStream->write(str.c_str(), str.size());
+  } else {
+    m_buffer.resize(std::max(m_buffer.size(), m_pos + str.size() + 1));
+    std::copy(str.begin(), str.end(), m_buffer.begin() + m_pos);
+  }
+
+  for (std::size_t i = 0; i < str.size(); i++) {
+    update_pos(str[i]);
+  }
+}
+
+void ostream_wrapper::write(const char* str, std::size_t size) {
+  if (m_pStream) {
+    m_pStream->write(str, size);
+  } else {
+    m_buffer.resize(std::max(m_buffer.size(), m_pos + size + 1));
+    std::copy(str, str + size, m_buffer.begin() + m_pos);
+  }
+
+  for (std::size_t i = 0; i < size; i++) {
+    update_pos(str[i]);
+  }
+}
+
+void ostream_wrapper::update_pos(char ch) {
+  m_pos++;
+  m_col++;
+
+  if (ch == '\n') {
+    m_row++;
+    m_col = 0;
+    m_comment = false;
+  }
+}
+}