function isDate(value) {
        return typeof value.getTime == "function" &&
            value.getTime() == value.valueOf();
    }
@name samsam.isDate
@param Object value

Returns true if the object is a ``Date``, or *date-like*. Duck typing
of date objects work by checking that the object has a ``getTime``
function whose return value equals the return value from the object's
``valueOf``.