Patches: **kwargs in errorbar and legend

By itself, this patch is completely pointless (exposing

    > isaxes is nonsense - setting this argument to False
    > indicates that the parent is *not* an axes. when
    > Legend.__init__ is called by axes.legend, the parent, of
    > course, is - by definition - an axes...)

Yes, this is meant to be used by figlegend....

JDH