C++17ification.

C++17ification!

- Filesystem interaction now uses std::filesystem::path.
- Usage of const char*, std::string have been changed to
  std::string_view where appropriate.
- Usage of printf-style functions changed to use fmt.

src/xenia/ui/ui_event.h

@@ -2,7 +2,7 @@
  ******************************************************************************
  * Xenia : Xbox 360 Emulator Research Project                                 *
  ******************************************************************************
- * Copyright 2014 Ben Vanik. All rights reserved.                             *
+ * Copyright 2020 Ben Vanik. All rights reserved.                             *
  * Released under the BSD license - see LICENSE in the root for more details. *
  ******************************************************************************
  */
@@ -10,6 +10,8 @@
 #ifndef XENIA_UI_UI_EVENT_H_
 #define XENIA_UI_UI_EVENT_H_
 
+#include <filesystem>
+
 namespace xe {
 namespace ui {
 
@@ -28,14 +30,14 @@ class UIEvent {
 
 class FileDropEvent : public UIEvent {
  public:
-  FileDropEvent(Window* target, const wchar_t* filename)
-      : UIEvent(target), filename_(filename) {}
+  FileDropEvent(Window* target, std::filesystem::path filename)
+      : UIEvent(target), filename_(std::move(filename)) {}
   ~FileDropEvent() override = default;
 
-  const wchar_t* filename() const { return filename_; }
+  const std::filesystem::path& filename() const { return filename_; }
 
  private:
-  const wchar_t* filename_ = nullptr;
+  const std::filesystem::path filename_;
 };
 
 class KeyEvent : public UIEvent {