Show progress if the operation takes longer than 2 seconds

I think it would be very helpful to see if an operation takes more time than usual or Blender just crashed. Therefore a progress pop-up window should appear for EVERY operation that takes longer than 2 seconds. I usually work with big scenes and high poly models, and sometimes a simple operation like packing UV islands takes 15 minutes (on models with several million polygons), and it's very time-consuming to wait 10-20 minutes than realize that Blender probably crashed, and starting over.

My humble thanks to every Blender developer, and keep up the good work guys!