pdInputMouse: new function for programmatically moving the cursor
pdInputKeyboard: new event for KeyUp events

KeyDown should be used when "hold-to-repeat" behavior is desired.

KeyUp should be used when only whole keypresses are desired.
Lasso selection: Backspace key now retreats the lasso by 10 pixels

Helpful for fixing lasso mistakes.  Note that Backspace will trigger a
retreat of *10 pixels on the image*, so if you use the tool while zoomed
out, the actual on-screen distance retreated might be less than 10
pixels.