set_xlim not "sticking"

I'm not sure if this is a bug or a feature, but limits set before
plotting aren't kept

sp = subplot(111)
sp.set_xlim([-5,5])
sp.plot(arange(-10,10),arange(-10,10))

displays from -10 to 9.

Axes.plot calls xaxis.autoscale_view() which undoes any previously set
limits. I haven't used matlab so I can't say what it does, but I'd
expect it to honor them (I think most plotting packages do). I looked
to alter Axis.plot to basically say

if xaxis.autoscale:
  xaxis.autoscale_view()

but currently there doesn't seem to be a way to discern whether the
current xaxis.viewlim was manually set or is the result of autoscale.
Should this be a feature (set_xlim "sticks")? Does Axis need an
autoscale attribute to enable this?

This is version 0.52 (which btw has matplotlib.version set to '0.51').

Thanks,
Greg