cs2103aug2014-w10-1c/main — pull request #169 by lowjoel (2014-10-08 07:18:42+00:00)
Title: Restructure the data store.

- Facades: Transaction and Data Store
- Internal: Transaction is a stack of operations, DataStore is a stack of transactions.
- When client code commits or rolls back transaction, facade forwards to real transaction, which tells the internal data store to apply the operations
- Move the logic for each action into the operation so that we fully utilise polymorphism

All tests pass. But I'm quite certain the tests are insufficient...