remove more dead code

public/javascripts/spacedeck_account.js

@@ -9,19 +9,12 @@ SpacedeckAccount = {
     account_tab: 'invoices',
     password_change_error: null,
     feedback_text: "",
-    importables: [], // spacedeck.com zip import files
   },
   methods: {
     show_account: function() {
       this.activate_dropdown('account');
     },
 
-    start_zip_import: function(f) {
-      if (confirm("Your archive will be imported in the background. This can take a few minutes. You can continue using Spacedeck in the meantime.")) {
-        import_zip(this.user, f);
-      }
-    },
-
     account_save_user_digest: function(val) {
       this.user.prefs_email_digest = val;
       this.save_user(function() {