Fixed CRUD to not create an entity factory upon each CRUD operation but once and then create an entity manager per transaction / CRUD operation.
1. Improved the database exceptions to bubble to controllers and output sensible message in header
2. Added a handler to clear the message that appears in the header for warnings
3. Improved the transactions by not performing a flus() and refresh() which I'm quite sure I don't want
4. Added table constraints to Stock and Portfolio to enforce UniqueConstraint and notNull
5. Added code to the same portfolio entity to not permit the same stock (since I couldn't get Sets to work)