* mh/rebase-fixup:
rebase -i: Retain user-edited commit messages after squash/fixup conflicts
t3404: Set up more of the test repo in the "setup" step
rebase -i: For fixup commands without squashes, do not start editor
rebase -i: Change function make_squash_message into update_squash_message
rebase -i: Extract function do_with_author
rebase -i: Handle the author script all in one place in do_next
rebase -i: Extract a function "commit_message"
rebase -i: Simplify commit counting for generated commit messages
rebase -i: Improve consistency of commit count in generated commit messages
t3404: Test the commit count in commit messages generated by "rebase -i"
rebase -i: Introduce a constant AMEND
rebase -i: Introduce a constant AUTHOR_SCRIPT
rebase -i: Document how temporary files are used
rebase -i: Use symbolic constant $MSG consistently
rebase -i: Use "test -n" instead of "test ! -z"
rebase -i: Inline expression
rebase -i: Remove dead code
rebase -i: Make the condition for an "if" more transparent