doubleClickF :: Time -> F a b -> F a b
doubleClickF timeout fudget
doubleClickF preprocesses the lowlevel input stream of a fudget to detect
and make it easier to deal with double clicks.
When two or more MouseButton{type'=Pressed,...}
events occur within the specified timeout,
the latter ones are converted into
MouseButton{type'=MultiClick n,...}
where n indicates how many times the mouse button was pressed.
timeout :: Timefudget :: F a b
Fudgets that use doubleClickF: textF.