move includes into project directory and create version header

include/greeter.h

@@ -1,31 +0,0 @@
-#pragma once
-
-#include <string>
-
-namespace greeter {
-
-  /**  Language codes to be used with the Greeter class */
-  enum class LanguageCode { EN, DE, ES, FR };
-
-  /**
-   * A class for saying hello in multiple languages
-   */
-  class Greeter {
-    std::string name;
-
-  public:
-    /**
-     * Creates a new greeter
-     * @param name the name to greet
-     */
-    Greeter(std::string name);
-
-    /**
-     * Creates a localized string containing the greeting
-     * @param lang the language to greet in
-     * @return a string containing the greeting
-     */
-    std::string greet(LanguageCode lang = LanguageCode::EN) const;
-  };
-
-}  // namespace greeter