Windows 11 start menu button support

- handling of `Taskbar alignment` setting (left/center)
  - start menu position is based on position of start button
  - mouse clicks to original button now work properly (without triggering original menu)
  - custom button is properly positioned
  - Win+X works properly

Src/Lib/ResourceHelper.h

@@ -67,6 +67,9 @@ bool IsWin10RS1( void );
 // Returns true if the version is Windows10 RS4 (Spring Creator Update) or later
 bool IsWin10RS4( void );
 
+// Returns true if the version is Windows11 or later
+bool IsWin11();
+
 // Wrapper for IShellFolder::ParseDisplayName
 HRESULT ShParseDisplayName( const wchar_t *pszName, PIDLIST_ABSOLUTE *ppidl, SFGAOF sfgaoIn, SFGAOF *psfgaoOut );
 
@@ -82,6 +85,12 @@ void StringUpper( CString &str );
 // Create a font from the user settings
 HFONT CreateFontSetting( const wchar_t *fontStr, int dpi );
 
+// Return DPI of given window (or system DPI on older systems)
+UINT GetDpi(HWND hwnd = nullptr);
+
+// Scale given value according to DPI of window
+int ScaleForDpi(HWND hwnd, int value);
+
 extern HINSTANCE g_Instance;
 
 const int ANIM_BUTTON_TAG1='ANM';