Fix column size for 1280px wide displays
I have no idea if this is the correct location for this merge request, if not, please feel free to tell me.
1280px is a very common screen width (1280x720, 1280x800, 1280x1024, 2560x1440 at 2x HiDPI = 1280x720). Yet Mastofe's minimum column size is just barely too high for this common resolution, introducing pointless "wiggle" and wasting a couple bottom pixels for a scrollbar.
This slight fix doesn't seem to introduce any issues either.