Make BlendSpace2D remember last point for BLEND_MODE_DISCRETE, and change it only if new point is closer.

[dznshfvt]

Well, I have an idea, I think. That it will be a lot better if BlendSpace will be able to remember it's last point and change to other point only if it is closer. If they are equal distance to, the last will be used. This will remove the preference in order, and i do believe that it will be very useful for 2d/pixel animations.