Add padding of 10% to the panning bounds

This helps avoiding being unable to see the region because the legend box is
over what you want, and you can't pan more to get it outside.
Raise resource query limit to 1000 lines

Ideally, we would get all lines from the resource, but it might be too much.
1000 lines feels like a reasonable limit. It would be good to somehow warn the
user that there's too much data.