Fixed two-finger touch delay, and all other hidden event-pile-up.

Added a processEvents() call in the idle, because otherwise calling idle updates starves the event handlers.

interface/src/Application.cpp

@@ -946,6 +946,11 @@ void Application::idle() {
     //  Only run simulation code if more than IDLE_SIMULATE_MSECS have passed since last time we ran
     
     if (diffclock(&_lastTimeIdle, &check) > IDLE_SIMULATE_MSECS) {
+        // We call processEvents() here because the idle timer takes priority over
+        // event handling in Qt, so when the framerate gets low events will pile up
+        // unless we handle them here.
+        processEvents();
+        
         update(1.0f / _fps);
         
         _glWidget->updateGL();