Trello Collapse Empty Lanes

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.