Bug 1376128 - Add eslint rules for testing/marionette; r=automatedtester,standard8

The eslint rules are based on the default, non-opinionated eslint rules
used throughout mozilla-central.  The testing/marionette eslint rules
are a specialisation of these based on the current coding style used.
These should not be contradictory to the overall JS code style that can
be inferred from the existing code base.

MozReview-Commit-ID: 2rKabgXXnu4

--HG--
extra : rebase_source : 724544b60b71db7c7b093a1ed51ebc77bc66482d

testing/marionette/.eslintrc.js

@@ -0,0 +1,18 @@
+"use strict";
+
+module.exports = {
+  "rules": {
+    "comma-dangle": ["error", "always-multiline"],
+    "indent": ["error", 2, {
+      "SwitchCase": 1,
+      "FunctionExpression": {"body": 1, "parameters": 2},
+      "MemberExpression": 2,
+    }],
+    "max-len": ["error", 78, {
+      "ignoreStrings": true,
+      "ignoreUrls": true,
+    }],
+    "no-new-object": "error",
+    "object-curly-spacing": ["error", "never"],
+  }
+};

testing/marionette/marionette.eslintrc.js

@@ -1,8 +0,0 @@
-// Parent config file for all marionette files.
-module.exports = {
-  // All globals made available in the test environment.
-  "globals": {
-    "ok": false,
-    "is": false,
-  }
-};