RRTimeslice: Updated output format to <range> #<seq>/<num>.
RRTimeslice: Updated output format to <range> #<seq>/<num>.

That is, format the timeslice in a range format (cf. tstzrange in PostgreSQL
9.2). I suppose this is easier to read for humans, even though it's a bit
longer. Also, include the number of timeslices in addition to the sequence
number as well. This way, we're able to unambiguously parse the output.

tokkee/postrr,tokkee/postrr