Completely run effEditIdle from a timer

Although it hasn't shown up, this will get rid of the possibility of
off-thread effEditIdle calls causing issues. And since we need some way
to run call this function while the event loop is running anyways, doing
it entirely from a timer similar to how hosts on Windows would do it
seems like the best solution.

src/wine-host/utils.h

@@ -226,7 +226,9 @@ class Win32Thread {
  */
 class Win32Timer {
    public:
+    Win32Timer();
     Win32Timer(HWND window_handle, size_t timer_id, unsigned int interval_ms);
+
     ~Win32Timer();
 
     Win32Timer(const Win32Timer&) = delete;