Use blocked scoped variables

In addition to using const and let, this also upgrades our linter config and removes lint (mostly whitespace).

package.json

@@ -41,7 +41,7 @@
     "copy-webpack-plugin": "^4.0.1",
     "coveralls": "3.0.0",
     "eslint": "4.15.0",
-    "eslint-config-openlayers": "7.0.0",
+    "eslint-config-openlayers": "^9.0.0",
     "expect.js": "0.3.1",
     "front-matter": "^2.1.2",
     "fs-extra": "5.0.0",
@@ -74,42 +74,6 @@
     "webpack-merge": "4.1.1"
   },
   "eslintConfig": {
-    "extends": "openlayers",
-    "parserOptions": {
-      "sourceType": "module"
-    },
-    "globals": {
-      "ArrayBuffer": false,
-      "Float32Array": false,
-      "Uint16Array": false,
-      "Uint32Array": false,
-      "Uint8Array": false,
-      "Uint8ClampedArray": false,
-      "ol": false,
-      "proj4": false
-    },
-    "rules": {
-      "no-constant-condition": 0,
-      "indent": [
-        2,
-        2,
-        {
-          "VariableDeclarator": 2,
-          "SwitchCase": 1,
-          "MemberExpression": 2,
-          "FunctionDeclaration": {
-            "parameters": 2,
-            "body": 1
-          },
-          "FunctionExpression": {
-            "parameters": 2,
-            "body": 1
-          },
-          "CallExpression": {
-            "arguments": 2
-          }
-        }
-      ]
-    }
+    "extends": "openlayers"
   }
 }