Greasy Fork

Yet more changes to the horrible auto-generated class names.

Also made it so it _waits_ for the page to finish rendering before it attempts to insert the additional buttons.
Should also re-insert the buttons if you navigate away from the backlog page and then back again. SPAs, what a brilliant idea...

Updated the CSS selector for the 'sprint filter' box _again_.

Replaced the big heap of chained '.parentNode' with a .closest() so it doesn't break as often.