fix format

lib/name_tree.js

@@ -6,19 +6,19 @@ import PDFObject from './object';
 
 class PDFNameTree {
 
-   constructor() {
+  constructor() {
     this._items = {};
   }
 
-   add(key, val) {
+  add(key, val) {
     return this._items[key] = val;
   }
 
-   get(key) {
+  get(key) {
     return this._items[key];
   }
 
-   toString() {
+  toString() {
     // Needs to be sorted by key
     const sortedKeys = (Object.keys(this._items)).sort((a, b) => a.localeCompare(b));
 
@@ -35,6 +35,6 @@ class PDFNameTree {
     out.push('>>');
     return out.join('\n');
   }
- }
+}
 
 export default PDFNameTree;