Makefile: remove .mailmap when cleaning
Makefile: docs target no longer depends on AUTHORS.md

The `docs' target is for users, `AUTHORS.md' for maintainers only.
Makefile: clean magit.info when in a git repository

Instead of when *not* in a repository.  That's how this was intended.
README.md: update magit.github.io links
README.md: rearrange a bit
README.md: use fenced code blocks for `sh' too

This makes the file more readable on Github, but also less
readable in Emacs.  Unfortunately we cannot have both.
README.md: fix typo
magit-status: add SAME-WINDOW argument
magit-visit-file-item: use magit-dired-jump

instead of dired-jump, directly.
magit-visit-file-item: visit submodules using magit-status
magit-mode-map: add binding for magit-dired-jump
Merge branch 'bugfix/1103'
magit-visit-file-item: cosmetics
magit-old-top-section: remove last traces of variable

Variable `magit-old-top-section' was removed some time ago, but in some
of the extensions it was still let-bound to nil, which used to result in
a minor speedup.  This no longer has any effect whatsoever, so remove
these let-bindings.
magit-wash-log: cosmetics
magit-stgit--enabled: remove variable and predicate

This was only used to disable the stgit menu entries when stgit is not
"enabled".  It also failed at doing that because it did not properly
invalidate the cache that was used by the predicate.  So we actually
gain something be removing this "feature".
magit-stgit.el: s/--/-/ in symbol names

While using "--" made sense for some of the renamed symbols, it did not
for others which because they aren't (or shouldn't be) internal-only
symbols.  Because we generally don't use "--" in symbol names in
Magit (which some exceptions), replace "--" with "-" in all stgit
symbols.
magit-stgit-extension-menu: move definition
magit-stgit-repair: show message when done
magit-stgit-rebase: show message when done