Update new scrolling

[Xanfre]

This includes a small change in how scrolling is detected to improve its behavior in extreme circumstances. It is not terribly important, but may be preferable for select users.
Following this, I think I will be able to leave that cursed text box alone.

[FenPhoenix]

To be clear, the fix is in the WParam stuff, right?
If so, I'll accept it but I'll remove the following code if you don't mind

case InteropMisc.WM_MBUTTONDOWN:
break;
case InteropMisc.WM_MBUTTONDBLCLK:
break;

as it prevents autoscroll which some people may want.

[Xanfre]

Yes, it just modifies the WParam values required to trigger the scroll events. On most machines, it likely will make no difference, but this is a more compatible implementation.

I removed the mentioned code, as it is true that some may find autoscrolling useful. Perhaps I should look into what is causing the cursor flickering exclusively in that function, as it is puzzling that it remains while all other forms of flickering in the readme box no longer occur.

[FenPhoenix]

If you find a solution for the autoscroll cursor flicker, I'd be happy to take a look at it. Meantime, accepting this pull request.