Basic type creation tests

[eparejatobes]

This is something that is easy to do without any data. I'm thinking about

• defining a test schema (maybe at the level of angulillos?)
• open an instance, create all the types and close gracefully

Once we have this we can move to things like type creation idempotence.

[eparejatobes]

There's already a basic test schema in bio4j/angulillos, and sample test data.