Biomedsheets

- Fixing `setup.py` to work with pip v10.t

- Fixing packaging to use base and not test dependencies.

- Removing some hard (transitive) dependencies.

- Fixing manifest so the package contains the JSON file.

- Allow cancer sheets for use in germline calling.
- Only warn if index has no NGS library, no error.

- Fixin TSV I/O.
- Bumping ruamel.yaml version.
- Fixing cancer sheet iteration.
- Allowing cancer-only samples in cance case sheets.
- Fixing `float`-related bug.
- Fixing bug in reference resolving (+tests)