Make all test databases root folder point to a valid location

See merge request !78

This will allow the docker tests to more easily setup and
cleanup its content.

While the folder is not used as these databases are generative
only, docker will create it anyway as mounting a non-exisiting
folder will trigger its creation with the daemon ownership
applied.

Pre commit cleanup

See merge request !77

- Add isort
- Update black repository reference
- Add ast check and case conflict check

Update flake8 configuration for line
length to match the one from black.

Handle error the same way for all algorithm types on execution

Closes beat.core#98

See merge request !75

Currently sequential and autonomous algorithms are not treating
errors happening in the process method the same way. This result
in missing information coming back up through beat/beat.core>

This patch fixes this and also ensure that the outputs are
properly closed.

Fixes beat.core#98

Add helper property to get the environment configured for the database

See merge request !74

Part of beat.core#64

Fixes a few warnings and depracations

See merge request !73

Update test execution environment to Python for tests

See merge request !72

Implement multiprocessing support for CachedDataSource

Closes #32

See merge request !71

These test ensure that DataLoaders can be used with
the multiprocessing module if these are passed through
a queue.

This will allow to pass an instance of it in
a queue when using the multiprocessing module.

This will allow to pass an instance of it in
a queue when using the multiprocessing module.

This allows to reset the state of a data source.

Currently only used by the CachedDataSource