Datasette-edit-schema

New features:
- Create a new table, setting the name of the primary key and adding multiple columns of different types. [5](https://github.com/simonw/datasette-edit-schema/issues/5)
- Set or change the primary key for a table. [1](https://github.com/simonw/datasette-edit-schema/issues/1)
- Add and edit foreign key relationships for a table. [7](https://github.com/simonw/datasette-edit-schema/issues/7)
- When altering a table, each column now shows a small sample of example values to help you decide the column's new name and type. [28](https://github.com/simonw/datasette-edit-schema/issues/28)
- Delete table button now asks for confirmation. [41](https://github.com/simonw/datasette-edit-schema/issues/41)

- Ability to create a new table. [5](https://github.com/simonw/datasette-edit-schema/issues/5)

- Ability to set or update a table's primary key. [1](https://github.com/simonw/datasette-edit-schema/issues/1)

- Preview of add and edit foreign keys. [7](https://github.com/simonw/datasette-edit-schema/issues/7)

- Fix for an error that occurs if you try to drop a column from a table that is part of a SQL view. [35](https://github.com/simonw/datasette-edit-schema/issues/35)

- Improved breadcrumbs for compatibility with Datasette 0.63+.