Fixed:
- Incompatibility with real database
- Improved connection code
- Inflexible dependency version ranges
- Poor code separation: moved general code from `model.py` to `metamodel.py`
Removed:
- `DagsToCreate` and `GeneticConstructs`, which were invalid
Added:
- `new_model` and `opened` context managers
- Test that checks each model class
- Support for `.chemfish/connection.json`
- Better main method, useful for testing with the active db