Biowdl-input-converter

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+ Make sure only one line of additional properties per sample is need in a
csv file.
+ Fix a bug where an empty field for an additional property in a csv
samplesheet would be defined as ``""`` instead of ``None``.

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+ Added documentation and readthedocs page
+ Added changelog and release procedures
+ Added test suite with coverage metrics, enabled CI
+ Add validate flag to allow users to validate files
+ Added command line interface with ability to write to stdout and files
+ Added ability to check files for presence and md5sum checking
+ Added sample group -> old style JSON/YAML conversion
+ Added sample group -> new style JSON/YAML conversion
+ Added yaml -> sample group conversion
+ Reworked csv conversion by DavyCats to fit the new sample group structure
+ Added sample group structure to enable any-to-any conversions