Remove unused storage.getFileContent

src/app/storage.js

 'use strict'
 
-var utils = require('./utils')
-
 function Storage () {
   this.rename = function (originalName, newName) {
     var content = this.get(originalName)
@@ -13,10 +11,6 @@ function Storage () {
     window.localStorage.removeItem(name)
   }
 
-  this.getFileContent = function (key) {
-    return this.get(utils.fileKey(key))
-  }
-
   this.exists = function (key) {
     return !!this.get(key)
   }