Merge remote-tracking branch 'origin/lei' into eidx

Merge remote-tracking branch 'origin/lei' into eidx

* origin/lei: (28 commits)
  lei: rename proposed "query" command to "q", add JSON output
  lei_xsearch: cross-(inbox|extindex) search
  lei: extinbox: start implementing in config file
  lei: revise output routines
  lei: support for -$DIGIT and -$SIG CLI switches
  build: add lei.sh + "make symlink-install" target
  lei: start working on bash completion
  lei: drop $SIG{__DIE__}, add oneshot fallbacks
  lei: restore default __DIE__ handler for event loop
  on_destroy: generic localized END
  lei_store: keyword extraction from mbox and Maildir
  lei_store: relax GIT_COMMITTER_IDENT check
  lei: micro-optimize startup time
  lei: rename $client => $self and bless
  lei: help: show actual paths being operated on
  lei: support pass-through for `lei config'
  rename LeiDaemon package to PublicInbox::LEI
  search: simplify initialization, add ->xdb_shards_flat
  lei_store: simplify git_epoch_max, slightly
  lei: support `daemon-env' for modifying long-lived env
  ...