Hide the picker on blur (by default)

Hey, thanks so much for this widget - it's great!  I had one tweak I needed for my purposes - to cause the monthpicker to hide on blur.  There was already an option to show on focus, so I just mimicked that; thought it might be useful to others so I'm pull requesting :-).

Let me know if I need to follow any particular procedure for merging this patch - thanks again for this!
~ Nate