Use hardware accelerated mouse cursor

[Alexey Torkhov]

Having mouse cursor lag is really disturbing, we should make it use hardware acceleration.

[Erik Ogenvik (erik-ogenvik)]

This is very much true. The main problem is however that SDL only supports black and white cursors, as described here: http://libsdl.org/cgi/docwiki.cgi/SDL_CreateCursor
We could of course go with that, but it would be nice to have a coloured cursor as we have now.
The suggested way in the SDL docs is to draw a SDL_Surface for the cursor, but I fear that that will work just as it does now (i.e. the cursor is only drawn once each Ember frame). So if we want to use coloured cursors I guess that we need to look at how to hook that up with lower level X calls instead (and corresponding win32 calls).