Add setting to display multiple fee tiers simultaneously

[chrnnburn]

Hey @marcgarreau! Really dig the app, super minimal and clean. I find myself often liking to split the difference between "Fast" and "Suggested" for my tx, would it be possible to add a setting to display multiple tiers at once in the menubar? Thanks!

[wolovim]

hey @chrnnburn, thanks for finding this app! i don't have time in the near future to add new features, but PRs welcome if you do! otherwise, i'll get to it at some point.