Add Exit button + controller led fix (#221)

runtime/include/aurora_events.h

@@ -58,6 +58,7 @@ inline void Flush(bool force = false) {
 // still active.  A window close is an intentional successful exit, so end the
 // process directly and do not run the crash/atexit paths.
 [[noreturn]] inline void ExitForAuroraWindowClose() noexcept {
+    settings_overlay::ReleaseControllers();
     WindowPlacementPersistence::Flush(true);
 #if defined(_WIN32)
     ::ExitProcess(0);

runtime/include/settings_overlay.h

@@ -12,4 +12,6 @@ void Draw() noexcept;
 bool StartupScreenVisible() noexcept;
 void NotifyStrapInputAccepted() noexcept;
 void AdvancePresentedFrame() noexcept;
+// Put host controllers back to a neutral state before the process ends.
+void ReleaseControllers() noexcept;
 } // namespace settings_overlay