Fix `arc diff --raw` when run outside a repository

Summary: Fixes T5071. If you run `arc diff --raw` from some arbitrary, non-repository directory we incorrectly try to read information out of the working copy. Even if this information is available, `arc diff --raw` should not assume it's accurate (there's no guarantee the diff comes from the working copy).

Test Plan: Ran `arc diff --raw` in an arbitrary directory.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T5071

Differential Revision: https://secure.phabricator.com/D9142
Move `getPEP8WithTextOptions` method into `ComprehensiveLintEngine` class.

Summary: Since this method is only used within this class, it makes sense to move it here.

Test Plan: N/A

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9114
Add a linter rule for determining when single quotes should be used over double quotes.

Summary: Personally, I am a strong fan of this rule. There is currently a similar rule provided by PHP_CodeSniffer.

Test Plan: Wrote and executed unit tests.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9117
Add some `.arclint` configuration options for `ArcanistJSHintLinter`.

Summary:
Allow `.jshintrc` and `.jshintignore` paths to be passed to `jshint`.

Ref T2039.

Test Plan: Added the `jshintrc` and `jshintignore` keys to an `.arclint` file that was configured to use `ArcanistJSHintLinter`. Ran `arc lint --trace` and inspected the flags that were passed to `jshint`.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: john.snow, epriestley, Korvin

Maniphest Tasks: T2039, T5085

Differential Revision: https://secure.phabricator.com/D9112
Set the working directory to the project root for external linter `ExecFuture` classes.

Summary: Fixes T5085. Currently, the `ExecFuture` instances that are used to call an external linter are executed in the current working directory. This means that if a path is specified in the `.arclint` file, relative to the project root directory, that the path will not be properly interpreted by the external linter when `arc lint` is called from a level deeper than the project root.

Test Plan: Ran `arc lint` from a subdirectory of a project and verified that the linter did not throw an exception due to not being able to find the specified configuration file.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley, Korvin

Maniphest Tasks: T5085

Differential Revision: https://secure.phabricator.com/D9159
Add an `ArcanistCoffeeLintLinter` linter.

Summary:
Add a wrapper around [[http://www.coffeelint.org/ | CoffeeLint]] as an `ArcanistExternalLinter`.

Depends on D9041.

Test Plan: Wrote and executed unit tests.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9051
Fix "arc diff --raw-command --create"

Summary: Fixes T5082. We try to access the repository API in some cases when we don't have one.

Test Plan:
  - Made revisions with "arc diff --raw-command --create".
  - Made this revision, without "--raw-command".

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T5082

Differential Revision: https://secure.phabricator.com/D9165
Merge branch 'master' of github.com:facebook/arcanist