1. Added Stock handling - portfolio to stocks a many:many relationship.  Can add a new stock for a portfolio or add an existing one.
2. Improved and unit tested the TabManager
3. Due to currently printing out stocks and portfolios (from the many:many relationship) I have to access them to force them to be fetched.  I could change to fetch.eager instead.
4. Did styling using the FXExperience CSS generator tool

TODO:
1. Fix Stock Model - currently a global one but need to have one per portfolio
2. Stock picking - don't want an existing stocks drop down and a box to add a new one.  Would prefer just a box and a realtime lookup is done as the user types to show existing stocks
3. Onwards and upwards with stock data, portfolio data persistence and so on