graph: Add '%bag-with-origins-node-type'.

* guix/scripts/graph.scm (bag-node-edges): Remove 'filter' call.  Add
case for 'origin'.
(%bag-node-type)[edges]: Add filtering here.
(%bag-with-origins-node-type): New variable.
(%node-types): Add it.
* tests/graph.scm ("bag DAG, including origins"): New test.
* tests/guix-graph.sh: Add 'bag-with-origins'.
* doc/guix.texi (Invoking guix graph): Document it.

doc: Mention the 'NIX_REMOTE' variable for 'guix import nix'.

Suggested by rgrau on #guix.

* doc/guix.texi (Invoking guix import): Document 'NIX_REMOTE'.

refresh: Add '--expression'.

* guix/scripts/refresh.scm (%options, show-help): Add --expression.
(guix-refresh): Honor it.
* doc/guix.texi (Invoking guix refresh): Document it.

Thank Jan.

guix download: Fail when more than one URL is passed.

* guix/scripts/download.scm (guix-download)[parse-option]: Call 'leave'
when passed an extra argument.
* tests/guix-download.sh: Add test.

guix download: Gracefully handle missing arguments.

Fixes <http://bugs.gnu.org/21991>.
Reported by Jan Synáček <jan.synacek@gmail.com>.

* guix/scripts/download.scm (guix-download): Call 'leave' when OPTS does
not contain an 'argument' key.

gnu: enca: Add file-name field to source.

* gnu/packages/textutils.scm (enca): Add file-name field to source.

gnu: recode: Add file-name field to source.

* gnu/packages/textutils.scm (recode): Add file-name field to source.

gnu: Fix a few 'source-file-name' lint warnings.

* gnu/packages/firmware.scm (ath9k-htc-firmware)[source](file-name): New
field.
* gnu/packages/gnunet.scm (guile-gnunet)[source](file-name): New field.
* gnu/packages/guile.scm (guile-next)[source](file-name): New field.
(guile-minikanren)[source](file-name): New field
(guile-gdbm-ffi)[source](file-name): New field.
* gnu/packages/ssh.scm (guile-ssh)[source](file-name): New field.

emacs: Expand 'guix-load-path'.

Reported by Mathieu Lirzin <mthl@gnu.org> at
<http://lists.gnu.org/archive/html/guix-devel/2015-11/msg00585.html>.

* emacs/guix-backend.el (guix-start-repl): Expand 'guix-load-path' to
  avoid a potentially relative directory name in Guile %load-path.

ftp-client: Default port for 'ftp-open' is now "ftp".

* guix/ftp-client.scm (ftp-open): Change default #:port to "ftp".
* guix/scripts/lint.scm (probe-uri): Remove 'port' parameter to
'ftp-open'.

ftp-client: Fix off-by-one when trying addresses in 'ftp-open'.

* guix/ftp-client.scm (ftp-open): Change to use 'match' instead of
car/cdr, and fix off-by-one (was '(null? addresses)' instead of
'(null? (cdr addresses))'.)

doc: Mention 'guix environment guix'.

* doc/contributing.texi (Building from Git): Mention 'guix environment
guix'.  Remove outdated description of ./bootstrap.  Clarify a few
things.

environment: Correctly handle abnormal exits.

Fixes <http://bugs.gnu.org/21958>.

* guix/scripts/environment.scm (status->exit-code): New procedure.
(exit/status, primitive-exit/status): Use it.
* tests/guix-environment-container.sh: Add test.

tests: Skip 'guix-container-environment.sh' when support is missing.

Fixes <http://bugs.gnu.org/21410>.
Reported by Alex Vong <alexvong1995@gmail.com>.

* tests/guix-environment-container.sh: Exit with 77 when
'((@@ (guix scripts environment) assert-container-features))' fails.

doc: Remove extraneous "See."

* doc/contributing.texi (Building from Git): Remove extra "See" and use
@xref instead of @pxref.

gnu: tig: Update to 2.1.1.

* gnu/packages/version-control.scm (tig): Update to 2.1.1.

gnu: cvs: Use external zlib.

* gnu/packages/version-control.scm (cvs)[arguments]: add configure flag
  --with-exernal-zlib.

gnu: nano: Update to 2.4.3.

* gnu/packages/nano.scm (nano): Update to 2.4.3.

refresh: Rewrite '--list-dependent' in terms of (guix graph).

* guix/scripts/refresh.scm (all-packages, list-dependents): New
procedures.
(guix-refresh): Use it.