Merge tag 'sparks-1.13.10' into develop

1.13.10
factorize the `SPARKS_DJANGO_SETTINGS` environment variable setup.
Always use env.root, else it doesn't work on local runs.
Explicit the local/remote Django settings load-fail errors.
previous factorization follow-up.
Implement the {make,compile}messages fabric tasks, with lang/apps/project auto-detection; works remotely too. Add the compile target to `runable()`.
bump version in setup.py
Merge branch 'release/1.14'