Backport VC improvements from trunk.

Backport VC improvements from trunk.

* vc/log-edit.el (log-edit-rewrite-fixes): New var.
(log-edit-author): New dynamic var.
(log-edit-changelog-ours-p, log-edit-insert-changelog-entries):
Use it to return the author if different from committer.
(log-edit-insert-changelog): Use them to add Author: and Fixes headers.

* vc/vc-hooks.el (vc-default-mode-line-string): Doc fix.

* vc/vc.el (vc-deduce-backend): New fun.  Handle diff buffers.
(vc-root-diff, vc-print-root-log, vc-log-incoming)
(vc-log-outgoing): Use it.
(vc-diff-internal): Set diff-vc-backend.

* vc/diff-mode.el (diff-vc-backend): New var.

* vc/vc.el (vc-diff-internal): Set `revert-buffer-function'
buffer-locally to lambda that re-runs the vc diff command.
(Bug#6447)

* vc/log-view.el (log-view-mode-map): Bind revert-buffer.

Make 'g' (AKA revert-buffer) rerun VC log, log-incoming and
log-outgoing commands.
* vc/vc.el (vc-log-internal-common): Add a new argument and use it
to create a buffer local revert-buffer-function variable.
(vc-print-log-internal, vc-log-incoming, vc-log-outgoing): Pass a
revert-buffer-function lambda.

Improve VC create/retrieve tag/branch.
* vc.el (vc-create-tag): Do not read the directory name for VCs
with repository revision granularity.  Adjust the tag/branch
prompt.  Reset VC properties.
(vc-retrieve-tag): Do not read the directory name for VCs
with repository revision granularity.  Reset VC properties.

Add optional support for resetting VC properties.
* vc-dispatcher.el (vc-resynch-window): Add new optional argument,
call vc-file-clearprops when true.
(vc-resynch-buffer): Add new optional argument, pass it down.
(vc-resynch-buffers-in-directory): Likewise.

Improve support for special markup in the VC commit message.
* vc-mtn.el (vc-mtn-checkin): Support Author: and Date: markup.
* vc-hg.el (vc-hg-checkin): Add support for Date:.
* vc-git.el (vc-git-checkin):
* vc-bzr.el (vc-bzr-checkin): Likewise.

Add support for vc-log-incoming, improve vc-log-outgoing for Git.
* vc-git.el (vc-git-log-view-mode): Fix font lock for
incoming/outgoing logs.
(vc-git-log-outgoing, vc-git-log-incoming): New functions.

* vc-git.el (vc-git-log-outgoing): Use the same format as the
short log.
(vc-git-log-incoming): Likewise.  Run "git fetch" before the log
command

Add bindings for vc-log-incoming and vc-log-outgoing.
* vc-hooks.el (vc-prefix-map): Add bindings for vc-log-incoming
and vc-log-outgoing.
* vc-dir.el (vc-dir-menu-map): Add menu bindings for vc-log-incoming
and vc-log-outgoing.

Improve state updating for VC tag commands.
* vc.el (vc-create-tag, vc-retrieve-tag): Call vc-resynch-buffer
to update the state of all buffers in the directory.

* vc-dir.el (vc-dir): Don't pop-up-windows.  (Bug#6204)

* vc.el (vc-checkin, vc-modify-change-comment):
Adjust to new vc-start/finish-logentry.
(vc-find-conflicted-file): New command.
(vc-transfer-file): Adjust to new vc-checkin.
(vc-next-action): Improve scoping.

* vc-git.el (vc-git-checkin): Use log-edit-extract-headers.
(vc-git-commits-coding-system): Rename from git-commits-coding-system.

* vc-dispatcher.el (vc-log-edit): Shorten names for
log-edit-show-files.

* vc-bzr.el (vc-bzr-checkin): Use log-edit-extract-headers.
(vc-bzr-conflicted-files): New function.

* log-edit.el (log-edit-summary, log-edit-header)
(log-edit-unknown-header): New faces.
(log-edit-headers-alist): New var.
(log-edit-header-contents-regexp): New const.
(log-edit-match-to-eoh): New function.
(log-edit-font-lock-keywords): Use them.
(log-edit): Insert a "Summary:" header as default.
(log-edit-mode): Mark font-lock rules as case-insensitive.
(log-edit-done): Cleanup headers.
(log-edit-extract-headers): New function to replace it.

* vc-dispatcher.el (vc-finish-logentry): Don't mess so badly with
the windows/frames.

* vc-bzr.el (vc-bzr-shelve-apply): Don't use *vc-bzr-shelve*.

* vc-dir.el (vc-dir-kill-line): New command.
(vc-dir-mode-map): Bind it to C-k.
(vc-dir-headers): Abbreviate the working dir.

* vc-git.el (vc-git-revision-table): Include remote branches.

New VC methods: vc-log-incoming and vc-log-outgoing.
* vc.el (vc-print-log-setup-buttons, vc-log-internal-common)
(vc-incoming-outgoing-internal, vc-log-incoming, vc-log-outgoing):
New functions.
(vc-print-log-internal): Just call vc-log-internal-common.
(vc-log-view-type): New permanent local variable.

* vc-hooks.el (vc-menu-map): Bind vc-log-incoming and vc-log-outgoing.

* vc-bzr.el (vc-bzr-log-view-mode): Use vc-log-view-type instead
of the dynamic bound vc-short-log.
(vc-bzr-log-incoming, vc-bzr-log-outgoing): New functions.

* vc-git.el (vc-git-log-outgoing): New function.
(vc-git-log-view-mode): Use vc-log-view-type instead
of the dynamic bound vc-short-log.

* vc-hg.el (vc-hg-log-view-mode): Use vc-log-view-type instead of
the dynamic bound vc-short-log.  Highlight the tag.
(vc-hg-log-incoming, vc-hg-log-outgoing): New functions.
(vc-hg-outgoing, vc-hg-incoming, vc-hg-outgoing-mode):
(vc-hg-incoming-mode): Remove.
(vc-hg-extra-menu-map): Do not bind vc-hg-incoming and vc-hg-outgoing.

Fix default-directory for vc-root-diff.
* vc.el (vc-root-diff): Bind default-directory to the root
directory for the diff command.

* vc-hg.el (vc-hg-push, vc-hg-pull): Use `apply' when calling
`vc-hg-command' with a list of flags.

* vc-bzr.el (vc-bzr-log-edit-mode): Add --fixes support to
log-edit-before-checkin-process.

* vc.el (vc-modify-change-comment): Pass MODE to vc-start-logentry.

* vc-bzr.el, vc-hg.el (log-edit-mode): Declare.

* vc-dispatcher.el (vc-start-logentry): Doc fix.
(log-view-process-buffer, log-edit-extra-flags): Declare.

Add special markup processing for commit logs.
* log-edit.el (log-edit): Add new argument MODE.  Use that mode
when non-nil instead of the log-view-mode.

* vc.el (vc-default-log-edit-mode): New function.

* vc-dispatcher.el (vc-log-edit): Add a mode argument, pass it to
log-edit.

Support for shelving snapshots and for showing shelves.
* vc-bzr.el (vc-bzr-shelve-show, vc-bzr-shelve-show-at-point)
(vc-bzr-shelve-apply-and-keep-at-point, vc-bzr-shelve-snapshot):
New functions.
(vc-bzr-shelve-map, vc-bzr-shelve-menu-map)
(vc-bzr-extra-menu-map): Map them.