tests/test-debugindexdot.t

progress: handle days, weeks and years

using hg clone svn://anonsvn.kde.org/home/kde/trunk kde ... with progress
yields 3008/1210830 1314h56m, which is unusable.

Add code to switch to days at 30 hours, to weeks at 15 days, and to years
at 55 weeks. A day has 24 hours, a week has 7 days, and a year has 52 weeks.
Months are intentionally omitted because they do not have a fixed length. The
Use of 52 weeks is a known and understandable estimate for a year.

It might make sense to spell our year to alert people when progress is
impractical, but...

Just exercize debugindexdot
Create a short file history including a merge.
  $ hg init t
  $ cd t
  $ echo a > a
  $ hg ci -qAm t1 -d '0 0'
  $ echo a >> a
  $ hg ci -m t2 -d '1 0'
  $ hg up -qC 0
  $ echo b >> a
  $ hg ci -m t3 -d '2 0'
  created new head
  $ HGMERGE=true hg merge -q
  $ hg ci -m merge -d '3 0'

  $ hg debugindexdot .hg/store/data/a.i
  digraph G {
  	-1 -> 0
  	0 -> 1
  	0 -> 2
  	2 -> 3
  	1 -> 3
  }