Uses angular-locker to store settings in localStorage

- settings.js now has its own module : 'jamstash.settings.controller'. This makes it easier to test it and identify what dependencies it has.
- Renames 'jamstash.settings' module into 'jamstash.settings.service'
- Adds an angular constant to hold the current Jamstash version in app.js.
- Adds a way to upgrade incrementally what was in localStorage : in 4.4.5, DefaultSearchType will no longer be an object but an int, so we must init it with an int value, otherwise a blank option will be displayed. We detect what version we are using and what version was stored using persistence-service.js and run the upgrade accordingly.

- Refactors almost completely persistence-service_test.js
- Unit-tests some of settings.js's methods.

app/common/utils-service.js

@@ -3,7 +3,7 @@
 *
 * Provides generally useful functions, like sorts, date-related functions, localStorage access, etc.
 */
-angular.module('jamstash.utils', ['jamstash.settings'])
+angular.module('jamstash.utils', ['jamstash.settings.service'])
 
 .service('utils', ['$rootScope', 'globals', function ($rootScope, globals) {
     'use strict';