Merge branch 'cc/signed-fast-export-import'

"git fast-export | git fast-import" learns to deal with commit and
tag objects with embedded signatures a bit better.

* cc/signed-fast-export-import:
  fast-export, fast-import: add support for signed-commits
  fast-export: do not modify memory from get_commit_buffer
  git-fast-export.adoc: clarify why 'verbatim' may not be a good idea
  fast-export: rename --signed-tags='warn' to 'warn-verbatim'
  fast-export: fix missing whitespace after switch
  git-fast-import.adoc: add missing LF in the BNF

diff --cc builtin/fast-import.c
Simple merge