Add eslint to Canvas

Rollout plan for this:
  1. Add necessary files and plugins to Canvas (this commit)
     - This will do nothing for many people, but those with eslint
       plugins in their editors will now start seeing linting stuff
       show up properly
     - These users can gradually add/remove rules as they see fit or
       where it makes sense.  The default rule set is from Airbnb with
       a few minor modifications to make things less difficult with the
       current codebase.
  2. Turn on warnings in the CI system (this commit + 1-2 months)
     - This would only apply to the diffs of new code
     - This will allow additional feedback from developers that don't
       already lint locally.  Rules can be adjusted as seen fit.
  3. Turn on failures in the CI system (this commit + 3-4 months)
     - Again this will be only for changed code, but at this point will
       start failing builds that don't follow the standards.
     - Changes to the rules can still be made here, but should be less
       frequent than those made in the previous 2 steps.

closes CNVS-32987

Test Plan:
  - Running eslint locally works
  - Editors pick up linting errors when configured properly

Change-Id: I93b7da735b96b472857120418c3c271a9ed6d429
Reviewed-on: https://gerrit.instructure.com/93969
Reviewed-by: Ryan Shaw <ryan@instructure.com>
Tested-by: Jenkins
Product-Review: Clay Diffrient <cdiffrient@instructure.com>
QA-Review: Clay Diffrient <cdiffrient@instructure.com>

.eslintrc.json

@@ -0,0 +1,27 @@
+{
+  "env": {
+    "es6": true,
+    "amd": true
+  },
+  "extends": "airbnb",
+  "parserOptions": {
+    "ecmaVersion": 7,
+    "ecmaFeatures": {
+      "experimentalObjectRestSpread": true,
+      "jsx": true
+    },
+    "sourceType": "module"
+  },
+  "parser": "babel-eslint",
+  "plugins": [
+    "react"
+  ],
+  "rules": {
+    "comma-dangle": ["error", "only-multiline"],
+    "max-len": ["warn", {"code": 140}],
+    "no-continue": ["off"],
+    "no-plusplus": ["off"],
+    "semi": ["off"],
+    "import/no-amd": ["off"]
+  }
+}

package.json

@@ -17,6 +17,7 @@
   "devDependencies": {
     "babel-cli": "^6.10.1",
     "babel-core": "^6.10.4",
+    "babel-eslint": "^7.1.0",
     "babel-loader": "^6.2.4",
     "babel-plugin-add-module-exports": "0.2.1",
     "babel-polyfill": "6.13.0",
@@ -29,6 +30,11 @@
     "compute-cluster": "0.0.9",
     "core-js-builder": "^2.4.1",
     "ember-template-compiler": "^1.8.0",
+    "eslint": "^3.9.0",
+    "eslint-config-airbnb": "^12.0.0",
+    "eslint-plugin-import": "^1.16.0",
+    "eslint-plugin-jsx-a11y": "^2.2.3",
+    "eslint-plugin-react": "^6.4.1",
     "exports-loader": "^0.6.2",
     "expose-loader": "^0.7.0",
     "gglobby": "0.0.3",

spec/javascripts/.eslintrc.json

@@ -0,0 +1,14 @@
+{
+    "env": {
+        "amd": true,
+        "qunit": true
+    },
+    "globals": {
+        "module": true,
+        "test": true,
+        "equal": true,
+        "ok": true,
+        "sinon": true,
+        "deepEqual": true
+    }
+}