Design block for pulse width based press/release

[andrewfstratton]

e.g.

Needs binding to time.pulse

N.B. Simpler for trigger but gets more complex for joystick, where the rate inverts on lower values ?!

Also will need to create a separate block for frequency based presses, e.g. to allow a rate/speed based pressing of a key, such as up arrow

May be the same block?