Use new SVN format for all property changes

Test Plan: `svn diff`

Reviewers: nh

Reviewed By: nh

CC: aran, epriestley

Differential Revision: https://secure.phabricator.com/D2799
Use pht() for plural
Wrap and simplify diff error excuse

Test Plan: Performed a lint error.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D2802
Document --ansi
Allow the "arc land --onto" default to be read from user config

Summary: Allow the default to be set in global config, not just project config.

Test Plan: `arc set-config arc.land.onto.default derp; arc land`

Reviewers: btrahan, vrana

Reviewed By: btrahan

CC: aran

Differential Revision: https://secure.phabricator.com/D2686
Move line to a better place
Add example to --ansi
Remove bogus warning in liberate
Warn about pht() with non constant string

Summary: We will extract them at some point, lint before it's too late.

Test Plan:
New test.
Linted all callsites.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D2825
[Arcanist] mercurial base commit DSL support

Summary:
This adds Mercurial support to the base commit DSL that's equivalent
to git's, though not identical.  Specifically, Mercurial has
arc:outgoing instead of arc:upstream, and hg:gca(commit) instead of
git:merge-base(commit), though they have similar behaviors.

Test Plan:
  [13:37:13 Thu Jun 21 2012] dschleimer@dev4022.snc6 ~/hg-dummy
  hg-dummy  20536 $ hg log -G -r master::
  @  changeset:   11:6970e9263ab8
  |  bookmark:    something
  |  tag:         tip
  |  user:        David Schleimer <dschleimer@fb.com>
  |  date:        Thu Jun 21 13:03:46 2012 -0700
  |  summary:     thing
  |
  o  changeset:   10:433a93023f03
  |  parent:      8:f47ccfe34267
  |  user:        David Schleimer <dschleimer@fb.com>
  |  date:        Thu Jun 21 13:03:34 2012 -0700
  |  summary:     some
  |
  | o  changeset:   9:c8379ef32b0d
  |/   bookmark:    other
  |    user:        David Schleimer <dschleimer@fb.com>
  |    date:        Thu Jun 21 13:01:04 2012 -0700
  |    summary:     other
  |
  o  changeset:   8:f47ccfe34267
  |  bookmark:    master
  |  user:        David Schleimer <dschleimer@fb.com>
  |  date:        Mon Jun 04 14:30:47 2012 -0700
  |  summary:     typo-fix
  |

  [13:38:00 Thu Jun 21 2012] dschleimer@dev4022.snc6 ~/hg-dummy
  hg-dummy  20536 $ ~/devtools/arcanist/bin/arc which --show-base --base hg:.^
  .^

  [13:38:11 Thu Jun 21 2012] dschleimer@dev4022.snc6 ~/hg-dummy
  hg-dummy  20536 $ ~/devtools/arcanist/bin/arc which --show-base --base 'hg:gca(other)'
  f47ccfe34267592dd2e336174a3a311b8783c024

  [13:38:21 Thu Jun 21 2012] dschleimer@dev4022.snc6 ~/hg-dummy
  hg-dummy  20536 $ hg id -r f47ccfe34267592dd2e336174a3a311b8783c024
  f47ccfe34267 master

  [13:38:31 Thu Jun 21 2012] dschleimer@dev4022.snc6 ~/hg-dummy
  hg-dummy  20537 $ ~/devtools/arcanist/bin/arc which --show-base --base 'arc:empty'
  null

  [13:38:44 Thu Jun 21 2012] dschleimer@dev4022.snc6 ~/hg-dummy
  hg-dummy  20538 $ hg id -r null
  000000000000

  [13:38:48 Thu Jun 21 2012] dschleimer@dev4022.snc6 ~/hg-dummy
  hg-dummy  20538 $ ~/devtools/arcanist/bin/arc which --show-base --base 'arc:outgoing'
  f47ccfe34267592dd2e336174a3a311b8783c024

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T1233

Differential Revision: https://secure.phabricator.com/D2822
Merge branch 'master' of http://github.com/facebook/arcanist