Return $this from didApplyPatch() shortcut

Test Plan: https://secure.phabricator.com/diffusion/ARC/browse/master/src/lint/patcher/ArcanistLintPatcher.php;bd7dc8abaa7bb4c0$75?view=blame

Reviewers: epriestley, jungejason

Reviewed By: jungejason

CC: aran

Differential Revision: https://secure.phabricator.com/D2101
Bump required PHP version

Test Plan:
  arc lint

Reviewers: epriestley

Reviewed By: epriestley

CC: aran

Differential Revision: https://secure.phabricator.com/D2127
Fix an issue with "arc diff --update" in Git on immutable workflows

Summary:
This should be a raw text block, not a parsed message object.

I broke this in rARC1f13e022cdc9bf4859274a83784bd615caf62ef9 when I improved Mercurial support.

See: https://github.com/facebook/arcanist/issues/23

Test Plan: (Will update this diff...)

Reviewers: vrana, jungejason, btrahan

Reviewed By: btrahan

CC: aran

Differential Revision: https://secure.phabricator.com/D2136
Make "--auto" the default for "arc diff"

Summary:
NOTE: This is a disruptive change to how 'arc diff' behaves by default.

Many years ago, Differential (then DiffCamp) supported SVN. Someone added a "-i" mode to the "diffcamp" script so you could "git show | diffcamp -i", and thus we were
forever bound to storing metadata in commit messages.

But this isn't a common use case outside of Facebook + git-svn, and isn't very flexible. We now have a great deal of flexibility to identify revisions based on
hashes, branch names, etc, and to sync metdata from web to CLI and back. I want to jettison the commit-message-bound artifacts of the tool's history, and move to a
more flexible, modern workflow.

I added "--auto" a while ago, which figures out if you want to create or update a diff automatically, and then prompts you for whatever data it needs, reading
information if it can from commit messages in the range. This is a vastly better workflow in general, especially for SVN and Mercurial users (who currently need to
jump to the web UI to create revisions). It's better for git users too, since they don't need to use template commits and don't have to muck with or configure
templates. However, it's a nontrivial change to git users' core workflow that is clearly different in more ways than it is clearly better.

  - This might be contentious, but probably not toooo much, I hope?
  - I also deleted the (fairly ridiculous) workflow where we sync commit message changes from the working copy. I think two or three people will be REALLY upset about
this but I have no sympathy. "--edit" covers this and has been around for like two years now, and making the commit message and web dual-authoritative was always a bad
idea that we only ever half-accommodated anyway (see giant swaths of removed TOOD nonsense).

Test Plan:
  - I've been using "--auto" exclusively for like a month, it seems to work well.
  - Created/updated SVN, Git and HG diffs with "arc diff" under this workflow.

Reviewers: btrahan, jungejason, nh

Reviewed By: btrahan

CC: Makinde, vrana, zeeg, mbautin, aran, yairlivne, 20after4

Maniphest Tasks: T614

Differential Revision: https://secure.phabricator.com/D2080
Add arc tasks command

Summary:
Added `arc tasks`:

%%%arc tasks
arc tasks --view-all    // View Open and Closed Tasks
arc tasks --by-status   // Group By Status
arc tasks --by-priority // Group By Priority%%%

Test Plan: Connect to conduit and run arc tasks >> make sure you have tasks =p

Reviewers: epriestley, indiefan

Reviewed By: epriestley

CC: aran, epriestley

Maniphest Tasks: T749

Differential Revision: https://secure.phabricator.com/D1943
Merge pull request #24 from Koolvin/arcpatch-D1943

Add arc tasks command