Add eslint to detect unhandled callback errors

.eslintignore

@@ -0,0 +1,20 @@
+node_modules/
+public/src/nodebb.min.js
+*.sublime-project
+*.sublime-workspace
+.project
+.vagrant
+.DS_Store
+logs/
+/public/templates
+/public/uploads
+/public/sounds
+/public/vendor
+/public/nodebb.min.js
+/public/acp.min.js
+/public/src/modules/string.js
+.idea/
+.vscode/
+*.ipr
+*.iws
+/coverage

.eslintrc.json

@@ -0,0 +1,6 @@
+{
+	"rules": {
+		"handle-callback-err": [ "error", "^(e$|(e|(.*(_e|E)))rr)" ]
+	}
+}
+

package.json

@@ -90,6 +90,7 @@
     "xregexp": "~3.1.0"
   },
   "devDependencies": {
+    "eslint": "^3.4.0",
     "grunt": "~0.4.5",
     "grunt-contrib-watch": "^1.0.0",
     "istanbul": "^0.4.2",