This patch was generated using clang-tidy:
clang-tidy -checks="-*,readability-inconsistent-declaration-parameter-name" -fix
(with some manual fixups of false-positives)
The formatting depending on the distance between two timestamps is
reintroduced with the responding function residing in the 'Ruler' class
(the prime user of that function).
Fixes a rounding bug for the least significant digit in the
'format_time_minutes()' function.
The 'Cursor' and 'CursorPair' classes now use the same precision when
formatting timestamps as the rest of the program.
This function is already complicated enough (it tries to guess in what
context it is currently used and changes its behaviour accordingly), so
remove the unused parameters to make it somewhat comprehensible.