[PATCHv1] git-p4: label import, tag export

This is an updated version of my earlier RFC/patch for importing p4 labels into git, incorporating comments from Pete Wyckoff, and git export support.

It operates by getting the sets of git tags and p4 labels, finding out what is missing, and creating tags/labels as necessary. This is in contrast to the existing detect-labels code which looks for p4 labels associated with the changelist being imported and which therefore misses tags on older changelists.

Git tag export is done during the sync phase because that's when the commit/changelist mapping is first known.

There is also a small fix to t9800 for a problem I found while testing this.

Luke Diamand (2):
  git-p4: fix t9800 editor check
  git-p4: import/export of labels to/from p4

 Documentation/git-p4.txt       |   39 ++++++-
 contrib/fast-import/git-p4     |  249 ++++++++++++++++++++++++++++++++++------
 t/t9800-git-p4-basic.sh        |    4 +-
 t/t9811-git-p4-label-import.sh |  145 +++++++++++++++++++++++
 4 files changed, 400 insertions(+), 37 deletions(-)
 create mode 100755 t/t9811-git-p4-label-import.sh