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.
remove unused option magit-log-show-gpg-status
magit-delete-{line,match}: new functions
magit-insert-child-count: remove trailing colon

A colon at the and of a heading still indicates that the number of child
sections should be shown at the end of the heading.  And so the strings
passed to most calls to `magit-insert-heading' still end with a colon.

However `magit-insert-child-count' now replaces the colon with " (N)"
instead of inserting that that string before the colon.
magit-popup: don't put colons after the keys
magit-insert-branch-description: move definition
rename "Progress Sections" to "Sequencer Section"

The new name matches Git terminology.
magit-show-or-scroll-{up,down}: improve doc-strings
magit-wip-{commit,save}-message: fix doc-strings
fix whitespace errors
restore behavior of "x" on a commit

Commit 11dc61ec479d671510e4c18ac73dfe096ad89518 intentionally changed
the behavior of pressing "x" on a commit.  Starting with that "x" did a
hard reset instead of a mixed reset, because "U" already does a mixed
reset.  Unfortunately many users would not notice this change until
they had already nuked some uncommitted changes.  So let's revert to
the old behavior.  "x" does a mixed reset again and "C-u x" has to be
used for a hard reset.

Add the new command `magit-revert' which behaves like
`magit-revert-head' used to do and bind "x" to it.  Locally I revert
this revert by binding "x" to `magit-revert-hard' again.
magit-stash-{apply,pop}: always respect magit-stash-popup-defaults

When `magit-stash-apply' and `magit-stash-pop' are called directly
(as opposed to from the popup) then explicitly check whether
`magit-stash-popup-defaults' contains "--index" and if so use it.

This is only a kludge and should be generalized, for several other
commands doing this would also make sense, but here it is especially
annoying that this feature doesn't exist yet, thus this kludge.
default to use per-repository buffers

Until now all buffers except for the status buffers where shared across
all repositories.  It was already possible to use per-repository buffers
for other modes too, but that was undocumented.

Replace all `magit-X-buffer-name' variables with properly documented
`magit-X-buffer-name-format' options and default to inserting the
absolute path to the toplevel of the current repository.

Also teach `magit-mode-get-buffer' what to do when `default-directory'
isn't below a git repository.
use symbols to represent the "diff status"
remove unused compatibility definitions
.travis.yml: update dependency urls
Merge branch 'master' into next

Conflicts:
	.travis.yml
	magit.el
always require package, sanitize usage
magit-dispatch-popup: bind "U" to magit-reset-index

Previously "U" was bound to `magit-unstage-all' but that was removed
because it is just a less flexible variant of `magit-reset-index'.