Fix phutil_is_utf8_with_only_bmp_characters() for partial valid characters

Summary:
We don't get partial 2-byte and 3-byte UTF8 characters quite correct, fataling instead of returning `false` because we access past the end of the string.

Instead, bail early if we run off the end of the string without seeing any issues.

Test Plan: Added and executed unit tests.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Differential Revision: https://secure.phabricator.com/D8321
Updated `.arcconfig` to match newer style configuration.

Summary: If I'm not mistaken, `project_id` was recently replaced by `project.name` and `conduit_uri` replaced by `phabricator.uri`.

Test Plan: I guess if this differential works, then everything is okay.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D8334
Minor linter fixes

Summary:
Fixed various linter issues that were identified with `arc lint --everything`.

- Changed tabs to spaces.
- Removed trailing newlines.
- Added whitespace on either side of binary operator.
- Added newline at EOF.
- Minor spelling fix.
- Removed leading newlines.

Test Plan: N/A

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D8335
Made the `AphrontWriteGuardExitEventListener` class final.

Summary: Self explanatory... Otherwise a linter warning is raised.

Test Plan: N/A

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D8350