Merge branch 'tc/last-modified'

A new command "git last-modified" has been added to show the closest
ancestor commit that touched each path.

* tc/last-modified:
  last-modified: use Bloom filters when available
  t/perf: add last-modified perf script
  last-modified: new subcommand to show when files were last modified

command-list.txt

@@ -124,6 +124,7 @@ git-index-pack                          plumbingmanipulators
 git-init                                mainporcelain           init
 git-instaweb                            ancillaryinterrogators          complete
 git-interpret-trailers                  purehelpers
+git-last-modified                       plumbinginterrogators
 git-log                                 mainporcelain           info
 git-ls-files                            plumbinginterrogators
 git-ls-remote                           plumbinginterrogators