Label & ticks spacing

    """ Public attributes transData - transform data coords

    > to display coords transAxis - transform axis coords to
    > display coords

    > """ LABELPAD = 5 --------------

You can use it:

  ax.xaxis.LABELPAD = 10
  ax.yaxis.LABELPAD = 10

We could make it a property and rc param, though, so it is consistent
with the rest of the API.

JDH