Clean up and tweak ESLint rules.

Also, refactor ESLint and stylelint config files; now everything will work from our root dir.

assets/js/.eslintrc.json

@@ -0,0 +1,26 @@
+{
+  "env": {
+    "es6": false,
+    "jquery": true
+  },
+  "parserOptions": {
+    "ecmaVersion": 5,
+    "sourceType": "script"
+  },
+  "extends": "../../.eslintrc.json",
+  "rules": {
+    // Best Practices
+    "no-magic-numbers": "off",
+    "vars-on-top": "off",
+
+    // Stylistic Issues
+    "spaced-comment": "off",
+
+    // ECMAScript 6
+    "no-var": "off",
+    "object-shorthand": "off",
+    "prefer-arrow-callback": "off",
+    "prefer-template": "off",
+    "prefer-rest-params": "off"
+  }
+}

assets/js/src/ie-emulation-modes-warning.js

@@ -41,6 +41,7 @@
   var nonEmulated = actualNonEmulatedIEMajorVersion()
 
   if (emulated !== nonEmulated) {
+    // eslint-disable-next-line no-alert
     window.alert('WARNING: You appear to be using IE' + nonEmulated + ' in IE' + emulated + ' emulation mode.\nIE emulation modes can behave significantly differently from ACTUAL older versions of IE.\nPLEASE DON\'T FILE BOOTSTRAP BUGS based on testing in IE emulation modes!')
   }
 }())