The phrases to create a database have a new 'find or' part

which allow them to not raise an error if the database already
exists.

This is useful when a setup script is run several times on the same
database and we don't want to have a failure just because the database
already exist.
Merge pull request #12 from guewen/create-db-already-exists

The phrases to create a database have a new 'find or' part