tests/test-backwards-remove.t

templatekw: allow getlatesttags() to match a specific tag pattern

This will allow the latest class of tag to be found, such as a release candidate
or final build, instead of just the absolute latest.  It will be exposed in a
future patch.

It's unfortunate that the original 'latesttags' cache can't be used to determine
the proper values, but it isn't fully populated for the entire repo.  For
example, the {latesttagdistance} keyword on the Mecurial repo builds the cache
up back to the revision for 1.4.  If the pattern was 're:^0\.\d$', that wouldn't
be in the cache.  Maybe this can be optimized some other way, but for now, this
is the simpliest implementation.

  $ hg init
  $ echo This is file a1 > a
  $ hg add a
  $ hg commit -m "commit #0"
  $ ls
  a
  $ echo This is file b1 > b
  $ hg add b
  $ hg commit -m "commit #1"
  $ hg co 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

B should disappear

  $ ls
  a