install/unarchive: add support for various fields

src/archives.js

@@ -2,6 +2,7 @@
 
 exports = module.exports = {
     get,
+    getIcons,
     getIcon,
     add,
     list,
@@ -14,8 +15,7 @@ const assert = require('assert'),
     database = require('./database.js'),
     eventlog = require('./eventlog.js'),
     safe = require('safetydance'),
-    uuid = require('uuid'),
-    _ = require('underscore');
+    uuid = require('uuid');
 
 const ARCHIVE_FIELDS = [ 'id', 'backupId', 'creationTime', 'appConfigJson', '(icon IS NOT NULL) AS hasIcon', '(appStoreIcon IS NOT NULL) AS hasAppStoreIcon' ];