Script to automate generation of fresh .ot data.

A starting point for autogenerating fresh .ot data. Next step will be to call this before every test, and exclude `ot-clean-data` from versioning.

This script starts working once those two pull requests are merged:
1. opentxs: [opentxs cli: introduce flag "--dummy-passphrase"](https://github.com/Open-Transactions/opentxs/pull/349)
2. opentxs-notary: [Add --only-init file that stops the server right after initialization.](https://github.com/Open-Transactions/opentxs-notary/pull/49)