Removed useless comments.

Summary: To me, it seems that these comments add no value. Personal opinion I suppose.

Test Plan: N/A

Reviewers: #blessed_reviewers, epriestley

Reviewed By: epriestley

CC: chad, Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D8382
Made `ArcanistNoLintTestCaseMisnamed` final.

Summary: Self explanatory.

Test Plan: `arc unit`

Reviewers: #blessed_reviewers, epriestley

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D8386
Simplified the logic in various functions.

Summary:
- Tidied up `ArcanistCSSLintLinter::getDefaultBinary`.
- Tidied up `CSSLintLinter::getDefaultFlags` function.
- Tidied up `ArcanistPhpcsLinter::getDefaultBinary` function.
- Tidied up `ArcanistPEP8Linter::getDefaultFlags` function
- Tidied up `ArcanistFlake8Linter::getDefaultFlags`.
- Tidied up `ArcanistCppcheckLinter::getLintOptions`.
- Tidied up `ArcanistCppcheckLinter::getLintPath`.
- Tidied up `ArcanistCpplintLinter::getLintOptions`.
- Tidied up `ArcanistCpplintLinter::getLintPath`.
- Removed child functions which are identical to the corresponding parent functions.

Test Plan: `arc lint` and `arc unit`.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: epriestley

CC: chad, Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D8385
Use PHP type hinting in `ArcanistXHPASTLinter`.

Summary: Explicitly specify the types of the function parameters.

Test Plan: `arc unit`

Reviewers: #blessed_reviewers, epriestley

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D8388
Correctly identify `@todo` comments as TODOs.

Summary: Allow `@todo` comments to be linted as TODOs as well as `TODO` comments.

Test Plan: I added a new test case (`todo.lint-test`)

Reviewers: #blessed_reviewers, epriestley

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D8389
Add "Changes Planned" and "In Preparation" states for revisions

Summary:
Ref T2222. Discussion in T4481. Ref T2543.

Primarily, this will let me fix some of the rough edges that came out of ApplicationTransactions and state-based transitions.

I'm also adding a constant for T2543 while I'm in here.

Test Plan: Used `grep` to look for any weird special behavior, didn't see any.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T2543, T2222

Differential Revision: https://secure.phabricator.com/D8400
Generate a documentation book for Arcanist

Summary: Ref T988. Not pretty or polished, but works fine.

Test Plan: Generated the docs, made sure they were all there.

Reviewers: chad, btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T988

Differential Revision: https://secure.phabricator.com/D8413
Merge branch 'master' of http://github.com/facebook/arcanist