Magnum's type names are fine, but I'd rather limit what depends on
Magnum as much as possible. Vector types are still allowed, though. No
way I'll write my own.
No need to redo the whole staged list when only one file gets updated.
Considering the call to refreshStagedMasses() is blocking (I might look
into threading stuff), its time complexity is O(n) at worst, which can
be bad on slower systems.
