Better autoranging for carpet plots

[alexcjohnson]

Currently the container axes for carpet plots are autoranged with a fixed percentage buffer around all edges of the carpet area. But for large carpets this is too much, and for small carpets too little - titles can get clipped - see eg cheaterslope.png which isn't even autoranged, it's manually ranged more generously, but the titles are still cut off.

Figuring out a better autorange than this would require sizing and calculating positions for the text upfront, then using that to pad the containing axes.

[gvwilson]

Hi - this issue has been sitting for a while, so as part of our effort to tidy up our public repositories I'm going to close it. If it's still a concern, we'd be grateful if you could open a new issue (with a short reproducible example if appropriate) so that we can add it to our stack. Cheers - @gvwilson