add support for using unicode characters when drawing log graphs

Add new function `magit-log-format-unicode-graph' and add it as a
choice in option `magit-log-format-graph-function'.  Also add new
option `magit-log-format-unicode-graph-alist' allowing users to
choose the characters (unicode or not, actually) to be used.
Merge pull request #1326 from jwiegley/master

Fix magit-key-mode.el to refer to magit-diff-toggle-refine-hunk
Transition machinery for magit-insert-pending-changes

If users have customized their `magit-status-sections-hook' then it can
be confusing when they update magit and suddenly start getting error
messages due to `magit-insert-pending-changes' not being defined
anymore. Define a an obsolete function alias to a shim function that
displays a message to the user about what's going on.

See also: 382351845eca2425713f640f9bb55756c9ddf723
Merge pull request #1328 from mgalgs/obsolete-alias

Transition machinery for magit-insert-pending-changes
Don't try to run magit-rewrite-diff-pending from magit-status-sections-hook

In [9a4e236: "Transition machinery for magit-insert-pending-changes"] an
obsolete function alias and "transition" function were introduced to
help users that may have customized `magit-status-sections-hook' to know
that `magit-rewrite-diff-pending' no longer exists. However, it really
never makes sense to run `magit-rewrite-diff-pending' from
`magit-status-sections-hook' and in some configurations the actual
"help" message is hidden by the error from
magit-rewrite-diff-pending. Fix this unnecessary confusion by *not*
running `magit-rewrite-diff-pending' from the shim function.
Merge pull request #1331 from mgalgs/rewrite-diff-pending-stuff

Don't try to run magit-rewrite-diff-pending from magit-status-sections-hook
stub test for magit-get-next-tag

Signed-off-by: Loic Dachary <loic@dachary.org>
Merge pull request #1340 from dachary/wip-test

stub test for magit-get-next-tag
magit-show: bugfix

`magit-diff-range' returns a cons cell of atoms.
magit-key-mode-popup-logging: support --no-merges option
Merge pull request #1341 from mgalgs/no-merges

magit-key-mode-popup-logging: support --no-merges option
magit-revert-buffer-hook: run in magit-revert-buffers
Merge remote-tracking branch 'origin/master'
magit-process-quote-arguments: flatten list of arguments
* magit-key-mode.el (magit-key-mode-add-group): add missing arguments
  list when creating new group.
Merge pull request #1347 from jtatarik/fix_add_group_arguments

magit-key-mode-add-group: add missing arguments list when creating new group
magit.text: mentioned that staging only works from status buffer
Package-Requires: add emacs-23.2
magit-process-setup: never collapse the section

Despite the face being used, too many users fail to realize that the
lines in the process buffer are sections and thus never try to show
the output by pressing TAB.

On the `next' branch this is being countered by creating all sections
expanded and only collapsing a section once the command returned
successfully, see 160ed937ff28bcf0c9fc84763376e7c88f3d836a.  That hasn't
made it to `master' yet, where we are doing something less reasonable.
So for now change `magit-process-setup' to never automatically collapse
a section.
.travis.yml: update dependency urls