Improve hg arc diff perf when image files are uploaded

Summary:
arc diff called 'hg cat' twice for every image binary in the diff.
This turns out to take 1 second per call on a large repo because mercurial
has to parse the manifest every time.

Now arc diff batches up all the files and does only two 'hg cat'
commands.  This makes the cost constant relative to the number of
images being uploaded.

Test Plan:
Ran arc diff on a diff with 30 images on both git and hg.
Verified that it was fast and that the images showed up in the web ui.

Reviewers: epriestley

Reviewed By: epriestley

CC: sid0, dschleimer, bos, aran, Korvin

Differential Revision: https://secure.phabricator.com/D5144
Render unit results progressively

Summary:
Some tests take longer (fixtures usually around 1 second for me) and also FB runs all tests on deploy.
I want to see all results immediately.

Test Plan:
Added `usleep(200000)` to `resultTest()`, then:

  $ arc unit
  Saw results printed one by one.

Also didn't pass `$renderer` to `ArcanistPhutilTestCase` and saw empty output.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5141
Use bookmark terminology if `arc land` on hg bookmark

Summary: Changes message for `arc land` that displays current branch or bookmark (if none is specified) to appropriately use the term 'bookmark' when on a bookmark in an hg repository.

Test Plan:
Ran `arc land` on new git and hg repositories, checking for correct identification of 'branch' or 'bookmark'.

~/test$ mkdir hg-test
~/test$ mkdir git-test
~/test$ cd hg-test
~/test/hg-test$ hg init
~/test/hg-test$ hg branch
default
~/test/hg-test$ hg bookmarks
no bookmarks set
~/test/hg-test$ arc land
Landing current branch 'default'.
Usage Exception: You can not land a branch onto itself -- you are trying to land 'default' onto 'default'. For more information on how to push changes, see 'Pushing and Closing Revisions' in 'Arcanist User Guide: arc diff' in the documentation. You may be able to 'arc amend' instead.
~/test/hg-test$ hg bookmark testmark
~/test/hg-test$ hg bookmarks
 * testmark                  -1:000000000000
~/test/hg-test$ hg branch
default
~/test/hg-test$ arc land
Landing current bookmark 'testmark'.
Usage Exception: Source testmark is a bookmark but destination default is not a bookmark. When landing a bookmark, the destination must also be a bookmark. Use --onto to specify a bookmark, or set arc.land.onto.default in .arcconfig.

Confirm still works on a git branch:

~/test/hg-test$ cd ../git-test/
~/test/git-test$ ls
~/test/git-test$ git init
Initialized empty Git repository in ~/test/git-test/.git/
~/test/git-test$ touch testfile
~/test/git-test$ git commit -am 'Test file'
~/test/git-test$ git branch
* master
~/test/git-test$ arc land
Landing current branch 'master'.
Usage Exception: You can not land a branch onto itself -- you are trying to land 'master' onto 'master'. For more information on how to push changes, see 'Pushing and Closing Revisions' in 'Arcanist User Guide: arc diff' in the documentation. You may be able to 'arc amend' instead.

Reviewers: DurhamGoode, epriestley

Reviewed By: DurhamGoode

CC: aran, epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D5163
Use hg phases to detect outgoing when phases are supported

Summary:
There was an accidental ! in the phase vs outgoing condition
which caused it to use 'hg outgoing' when it should have used the draft()
phase.  Fixing this shaves 4.5 seconds off 'arc diff' on large repos.

Test Plan:
Ran arc diff --trace.  Noted that the draft() was used and that the diff
contained the correct files and commit.

Reviewers: epriestley

Reviewed By: epriestley

CC: sid0, bos, dschleimer, aran, Korvin

Differential Revision: https://secure.phabricator.com/D5182
Respect British spelling also in arguments

Summary: These are the errors I really do.

Test Plan:
  $ arc diff --no-lint
  (Assuming '--no-lint' is the British spelling of '--nolint'.)
  $ arc diff --reviewer a
  (Assuming '--reviewer' is the British spelling of '--reviewers'.)

New unit test.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5185
`arc feature` set up git tracking branch

Summary:
When using arc feature, it should set up the tracking branch to be
master.

Test Plan:
  ./bin/arc feature tracking

Reviewers: vrana, epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5169
Merge branch 'master' of http://github.com/facebook/arcanist