Run eslint in tools/lint-all with npm run --silent lint

This commit adds a basic eslintrc that emulates jslint defaults.
Rules that conflict with our existing code have been switched to
warnings instead of errors. Globals have been added to the eslintrc. The
bundled js file (generated by webpack) and blueslip.js are ignored with
.eslintignore.

To display warnings, run npm run lint-loud. This runs eslint without the
--quiet option on static/js and frontend_tests.

npm run --silent lint is run by tools/lint-all (in addition to jslint).
The --silent option is used to suppress the default output from npm run.

Fixes #535.

.eslintignore

@@ -0,0 +1,4 @@
+static/js/bundle.js
+static/js/blueslip.js
+puppet/zulip_ops/files/statsd/local.js
+tools/jslint/check-all.js

.eslintrc

@@ -0,0 +1,177 @@
+{
+    "env": {
+        "node": true
+    },
+    "globals": {
+        "$": false,
+	"_": false,
+	"jQuery": false,
+	"Spinner": false,
+	"Handlebars": false,
+	"XDate": false,
+	"zxcvbn": false,
+	"LazyLoad": false,
+	"Dropbox": false,
+	"SockJS": false,
+	"marked": false,
+	"i18n": false,
+	"bridge": false,
+	"page_params": false,
+	"status_classes": false,
+	"password_quality": false,
+	"csrf_token": false,
+	"typeahead_helper": false,
+	"popovers": false,
+	"server_events": false,
+	"ui": false,
+	"stream_color": false,
+	"people": false,
+	"navigate": false,
+	"settings": false,
+	"resize": false,
+	"loading": false,
+	"compose": false,
+	"compose_fade": false,
+	"subs": false,
+	"timerender": false,
+	"message_edit": false,
+	"reload": false,
+	"composebox_typeahead": false,
+	"search": false,
+	"topic_list": false,
+	"gear_menu": false,
+	"hashchange": false,
+	"message_list": false,
+	"Filter": false,
+	"pointer": false,
+	"util": false,
+	"MessageListView": false,
+	"blueslip": false,
+	"rows": false,
+	"WinChan": false,
+	"muting_ui": false,
+	"Socket": false,
+	"channel": false,
+	"viewport": false,
+	"avatar": false,
+	"feature_flags": false,
+	"search_suggestion": false,
+	"referral": false,
+	"notifications": false,
+	"message_flags": false,
+	"bot_data": false,
+	"stream_list": false,
+	"narrow": false,
+	"admin": false,
+	"stream_data": false,
+	"muting": false,
+	"Dict": false,
+	"unread": false,
+	"alert_words_ui": false,
+	"message_store": false,
+	"favicon": false,
+	"condense": false,
+	"floating_recipient_bar": false,
+	"tab_bar": false,
+	"emoji": false,
+	"activity": false,
+	"invite": false,
+	"colorspace": false,
+	"tutorial": false,
+	"templates": false,
+	"alert_words": false,
+	"fenced_code": false,
+	"echo": false,
+	"localstorage": false,
+	"current_msg_list": true,
+	"home_msg_list": false,
+	"pm_list": false,
+	"unread_ui": false
+    },
+    "rules": {
+        "no-alert": 2,
+        "no-array-constructor": 2,
+        "no-caller": 2,
+        "no-bitwise": 2,
+        "no-catch-shadow": 2,
+        "comma-dangle": 0,
+        "no-console": 1,
+        "no-control-regex": 2,
+        "no-debugger": 2,
+        "no-div-regex": 2,
+        "no-dupe-keys": 2,
+        "no-else-return": 1,
+        "no-empty": 1,
+	"no-empty-character-class": 2,
+        "no-eq-null": 2,
+        "no-eval": 2,
+        "no-ex-assign": 2,
+        "no-extra-semi": 2,
+        "no-func-assign": 2,
+        "no-floating-decimal": 2,
+        "no-implied-eval": 2,
+        "no-with": 2,
+        "no-fallthrough": 2,
+        "no-unreachable": 2,
+        "no-undef": 2,
+        "no-undef-init": 2,
+        "no-unused-expressions": 2,
+        "no-octal": 2,
+        "no-octal-escape": 2,
+        "no-obj-calls": 2,
+        "no-multi-str": 2,
+        "no-new-wrappers": 2,
+        "no-new": 2,
+        "no-new-func": 2,
+        "no-native-reassign": 2,
+        "no-plusplus": 1,
+        "no-delete-var": 2,
+        "no-return-assign": 2,
+        "no-new-object": 2,
+        "no-label-var": 2,
+        "no-ternary": 0,
+        "no-self-compare": 2,
+        "no-sync": 2,
+        "no-underscore-dangle": 1,
+        "no-loop-func": 1,
+        "no-labels": 2,
+        "no-unused-vars": 1,
+        "no-script-url": 2,
+        "no-proto": 2,
+        "no-iterator": 2,
+        "no-mixed-requires": [0, false],
+	"no-extra-parens": ["error", "functions"],
+        "no-shadow": 1,
+        "no-use-before-define": 2,
+        "no-redeclare": 2,
+        "no-regex-spaces": 2,
+        "brace-style": [1, "1tbs"],
+        "block-scoped-var": 0,
+        "camelcase": 1,
+        "complexity": [0, 4],
+        "curly": 2,
+        "dot-notation": 2,
+        "eqeqeq": 2,
+        "guard-for-in": 0,
+        "max-depth": [0, 4],
+        "max-len": [0, 80, 4],
+        "max-params": [0, 3],
+        "max-statements": [0, 10],
+        "new-cap": 1,
+        "new-parens": 2,
+        "one-var": 1,
+        "quotes": [1, "single"],
+        "quote-props": 0,
+        "radix": 0,
+        "semi": 2,
+        "keyword-spacing": 1,
+        "space-before-blocks": 1,
+        "strict": 1,
+        "unnecessary-strict": 0,
+        "use-isnan": 2,
+        "valid-typeof": 0,
+        "wrap-iife": 2,
+        "wrap-regex": 0,
+        "yoda": 1
+    }
+}

frontend_tests/.eslintrc

@@ -0,0 +1,16 @@
+{
+    "env": {
+	"shared-node-browser": true
+    },
+    "globals": {
+	"assert": false,
+	"add_dependencies": false,
+	"casper": false,
+	"document": false,
+	"set_global": false,
+	"window": false
+    },
+    "rules": {
+	"no-sync": 1
+    }
+}

package.json

@@ -16,17 +16,21 @@
     "webpack": "1.12.2"
   },
   "devDependencies": {
+    "casperjs": "1.1.3",
+    "cssstyle": "0.2.29",
+    "eslint": "^3.9.1",
+    "htmlparser2": "3.8.3",
     "istanbul": "0.4.0",
     "jsdom": "9.4.1",
-    "xmlhttprequest": "1.5.0",
     "nwmatcher": "1.3.6",
-    "htmlparser2": "3.8.3",
-    "cssstyle": "0.2.29",
-    "webpack-dev-server": "1.12.1",
     "phantomjs-prebuilt": "2.1.7",
-    "casperjs": "1.1.3"
+    "webpack-dev-server": "1.12.1",
+    "xmlhttprequest": "1.5.0"
+  },
+  "scripts": {
+    "lint": "eslint --quiet",
+    "lint-loud": "eslint static/js frontend_tests"
   },
-  "scripts": {},
   "repository": {
     "type": "git",
     "url": "https://github.com/zulip/zulip.git"

static/js/.eslintrc

@@ -0,0 +1,5 @@
+{
+    "env": {
+        "browser": true
+    }
+}

tools/lint-all

@@ -492,6 +492,13 @@ def run():
                                      + by_lang['js'])
             return result
 
+        @lint
+        def eslint():
+            # type: () -> int
+            result = subprocess.call(['npm', 'run', '--silent', 'lint']
+                                     + by_lang['js'])
+            return result
+
         @lint
         def puppet():
             # type: () -> int