build: introduce 'make doclint' command and tooling

This adds remark-lint tooling and introduces a 'make doclint' command,
which is also executed on 'make test' runs.

tools/remark-cli dir was created by installing `remark-cli` and
`remark-lint`, the following files and directories are being excluded:
 * `./node_modules/concat-stream/node_modules/readable-stream/`
   a duplicate copy of `readable-stream` of 2.0, there already is 2.1.
 * `./**/doc/`, `./**/test/` -- docs and tests for deps are not needed.
 * `./**/history.md` and `./**/changelog.md` (case-insensitive).
 * `./**/.travis.yml`, `./**/.istanbul.yml`, `./**/.zuul.yml`.
 * `./**/.eslintrc`, `./**/.jscs.json`, `./**/.jshintrc`.
 * `./**/.npmignore`, `./**/component.json`, `./**/.gitattributes`.
 * `./**/dist/` (affects `sprintf-js` and `js-yaml`), not `require()`-d.

PR-URL: nodejs#8551

.eslintignore

@@ -5,5 +5,6 @@ test/fixtures
 test/disabled
 test/tmp*/
 tools/eslint
+tools/remark-cli
 node_modules
 benchmark/tmp/

Makefile

@@ -196,6 +196,7 @@ test: all
 	$(MAKE) cctest
 	$(PYTHON) tools/test.py --mode=release -J \
 		addons doctool inspector known_issues message pseudo-tty parallel sequential
+	$(MAKE) doclint
 	$(MAKE) lint
 
 test-parallel: all
@@ -816,6 +817,9 @@ jslint-ci:
 	$(NODE) tools/jslint.js $(PARALLEL_ARGS) -f tap -o test-eslint.tap \
 		benchmark lib test tools
 
+doclint:
+	$(NODE) tools/remark-cli/cli.js -qf *.md doc src lib benchmark tools/doc/*.md tools/icu/*.md
+
 CPPLINT_EXCLUDE ?=
 CPPLINT_EXCLUDE += src/node_root_certs.h
 CPPLINT_EXCLUDE += src/queue.h

tools/remark-cli/cli.js

@@ -0,0 +1,34 @@
+#!/usr/bin/env node
+/**
+ * @author Titus Wormer
+ * @copyright 2015 Titus Wormer
+ * @license MIT
+ * @module remark:cli
+ * @fileoverview CLI to process markdown.
+ */
+
+'use strict';
+
+/* Dependencies. */
+var start = require('unified-args');
+var extensions = require('markdown-extensions');
+var processor = require('remark');
+var proc = require('remark/package.json');
+var cli = require('./package.json');
+
+/* Start. */
+start({
+  processor: processor,
+  name: proc.name,
+  description: cli.description,
+  version: [
+    proc.name + ': ' + proc.version,
+    cli.name + ': ' + cli.version
+  ].join(', '),
+  pluginPrefix: proc.name,
+  presetPrefix: proc.name + '-preset',
+  packageField: proc.name + 'Config',
+  rcName: '.' + proc.name + 'rc',
+  ignoreName: '.' + proc.name + 'ignore',
+  extensions: extensions
+});