largefiles: fix largefiles+subrepo update (issue3752) Override updaterepo() instead of individual methods that may not be called for each subrepo. Add test. Based on patch from Matt Harbison. Changes the order of update-related messages (now largefiles comes before the global status).

     1

Greg Ward, author of the original bfiles extension

     2

Na'Tosha Bard of Unity Technologies

     3

Fog Creek Software

     4

Special thanks to the University of Toronto and the UCOSP program