Fix some bugs with default assignments, improve specs

Three fixes: 

* fixes an issue where a class has been persisted with super serial data and when you add an entry to super serialize, the new entry does not show up until the class is saved again 
* fixes the case where a class is persisted without super serialize and then it is added later
* fixes the spec for super serialize to clean itself up between tests. Since there is so much class-based meta, we need to clear the db table and reload the class to ensure the tests are isolated.