Lint `TRUE`, `nUlL`, etc., for Phabricator conventions

Summary: Detect and fix unconventional spellings of `true`, `false`, `null` and `array` (these are the only keywords I've seen spelled unconventionally in the wild).

Test Plan: Unit tests.

Reviewers: DurhamGoode, btrahan, vrana

Reviewed By: vrana

CC: aran

Maniphest Tasks: T2985

Differential Revision: https://secure.phabricator.com/D5686
Construct a diganostic parser in BaseWorkflow::getChange()

Summary:
@ender is reporting a parsing issue in SVN, but we don't build a parser with setWriteDiffOnFailure() set in this workflow right now so I can't get the raw file to fix the issue.

Use the onboard mechanism to build a parser with `setWriteDiffOnFailure()` set, so it will write the diff, so I can get a copy so I can fix the problem.

Test Plan: Ran `arc diff --preview` in an SVN repo with a linter.

Reviewers: ender, btrahan

Reviewed By: ender

CC: aran

Differential Revision: https://secure.phabricator.com/D5699
Fix hg amend during arc diff

Summary:
When doing an arc diff with pending changes in your working copy
it was creating a new commit with the pending changes instead of amending
the existing one.  The problem was the author comparison was comparing
values like "John Smith <john@foo.com>" with "John Smith". The fix changes
$api->getAuthor() to return "John Smith" instead of the full string. This
matches the behavior (and implementation) found in the git api.

Test Plan:
hg book foo
touch a && hg commit -Ama
touch b && hg add b
arc diff
When prompted, amend the pending changes to the existing commit.

Verified that the changes were amended instead of making a new commit.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5706
Enable lint amending commits in mercurial

Summary:
arc lint was hardcoded for git for amending commits with lint
patches. This enables the same functionality for mercurial.

Test Plan:
Made some changes that would result in a lint patch.
arc diff

Verify that the patches it produces were amended into the commit.

Verified it still works in git as well.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5716
Add a configuration for python path

Test Plan: not a clue

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5717
Merge branch 'master' of http://github.com/facebook/arcanist