v0.5.0

* Added a new `stream` method to allow the streaming of large datasets from the database.
* Added a new `isolate` option to `db.transaction` to ensure that the transaction is not nested inside of a concurrently running transaction.
* Added more indepth error handling to connections on all database adapters.
* Refactored `fetchRows`, and `execute` to be common between adapters.
* Updated Readme with better examples.