Pushed a simple but quite important fix yesterday.

As you may know, cursors are rendered in HW these days. One benefit of this is that the cursor doesn't flicker when it is moved around. Another one is that the cursor is responsive even when the computer is under load. (This has to do with the server implementation, not with the hardware. HW cursors are updated during SIGIO handling, not during event processing, hence the responsiveness)

Unfortunately, current hardware can't render arbitrary numbers of cursors, and although anholt claims that he has ideas of how to render two cursors in HW, I understand we'll be stuck with SW rendering for a while (cursors, DRI works nonetheless). SW cursors are bad, since they can be laggy. I've been using it for a while at home, and it can be quite annoying.

The solution: MPX now switches between HW and SW rendering. As long as we have only a single cursor, we use HW rendering. When the second cursor is created, the server switches to SW cursors, and then back again to HW when only one cursor is left.

The side-effect: I could now drop MPX onto your machine and you wouldn't even notice that it's there until you start creating new devices. Yay.