Percent-ships-departed

percent-ships-departed
        Boolean function which returns true if the percentage of ships in the listed ships and wings which have departed is
greater or equal to the given percentage.  For wings, all ships of all waves are used for calculation for the total possible
ships to depart.

Takes 2 or more arguments:
        1:      Percentge of departed ships at which this function will return true.
        2+:     List of ships/wing whose departure status should be determined.