Trello Collapse Empty Lanes per daf

If you've ever worked with a really wide board in Trello, you'll know how much empty lanes just get in the way - especially if you've applied a filter and basically only a few lanes are valid, with swaths of empty lanes in between which require horizontal scrolling to navigate around. Perhaps your board _is_ too wide, but perhaps you don't have control over it! This extension hopes to reduce your frustration with wide Trello boards.