Issue 3692 - Add base ESLint configuration

eslint-config-eyeo/index.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2017 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 17 matching lines @@
     "array-bracket-spacing": "error",
     "arrow-spacing": "error",
     "block-scoped-var": "error",
     "block-spacing": "error",
     "brace-style": ["error", "allman", {allowSingleLine: true}],
     "camelcase": ["error", {properties: "never"}],
     "comma-dangle": "error",
     "comma-spacing": "error",
     "comma-style": "error",
     "computed-property-spacing": "error",
-    "curly": ["error", "multi-or-nest", "consistent"],
+    "curly": ["error", "multi-or-nest"],
     "eol-last": "error",
     "func-call-spacing": "error",
     "indent": ["error", 2, {SwitchCase: 1, ArrayExpression: "first"}],
     "key-spacing": "error",
     "keyword-spacing": "error",
     "linebreak-style": "error",
     "lines-around-directive": "error",
     "max-len": ["error", 80, {ignoreUrls: true}],
     "new-parens": "error",
     "no-array-constructor": "error",
     "no-caller": "error",
     "no-case-declarations": "off",
     "no-catch-shadow": "error",
     "no-cond-assign": "off",
     "no-console": ["error", {allow: ["warn", "error", "trace"]}],
     "no-control-regex": "off",
     "no-else-return": "error",
     "no-empty": ["error", {allowEmptyCatch: true}],

[kzar, 2017/02/13 09:27:09]

(Without this ESLint complained about empty blocks after a try... catch...,
which is something we do in adblockpluscore.)

     "no-eval": "error",
     "no-extra-bind": "error",
     "no-extra-label": "error",
     "no-implied-eval": "error",
     "no-labels": ["error", {allowLoop: true}],
     "no-lone-blocks": "error",
     "no-lonely-if": "error",
     "no-multi-spaces": "error",
     "no-new-func": "error",
     "no-new-object": "error",
     "no-proto": "error",
     "no-self-compare": "error",
+    "no-shadow": "error",
     "no-trailing-spaces": "error",
     "no-unneeded-ternary": "error",
     "no-unused-vars": "off",
     "no-useless-computed-key": "error",
     "no-useless-concat": "error",
     "no-useless-escape": "error",
     "no-useless-return": "error",
     "no-var": "error",
     "no-warning-comments": "error",
     "no-whitespace-before-property": "error",
@@ skipping 25 matching lines @@
     "strict": ["error", "global"],
     "valid-jsdoc": ["error", {
       requireParamDescription: false,
       requireReturn: false,
       requireReturnDescription: false
     }],
     "yield-star-spacing": "error",
     "yoda": "error"
   }
 };