Block simulation delay

[cpseager]

Now that we are moving motors in 'real time' the block 'highlight delay' can significantly affect the motor position (and also the reaction time to a sensor changing).

I think we should reduce the simulation delay as much as possible, so that it is still possible to see the blocks change in sequence, but only just! To keep it simple a speed slider is probably not required here, or do you think it is worth adding?

Also would be better if 'waits' didn't have any extra 'simulation' delay added at all so they are more accurate (they don't need it, as sim will highlight that block for the wait duration anyway)?

[cpseager]

Speeded up for now via 49245c0