[Feature Request] Sliding window

[stof]

Currently, the pagination window is not centered on the current page. If you are on the page 10, you have handles for the pages 1 to 10. It would be easier to use if the handles would go from page 6 to 15 in this case

[excentris]

Is somebody working on this?

[wyuenho]

Still here. It would be nice if someone can write a test for this so I can merge it. If not, I'll deal with this in a few days. I plan to release Backgrid 0.3.0 this week.