Changed aria header docstrings in rest format

README.rst

aria/__init__.py

aria/aria2.py

aria/check.py

aria/conbox/ndconv.py

aria/conbox/protmap.py

aria/core/Analyser.py

aria/core/AriaPeak.py

aria/core/AriaXML.py

aria/core/Assignment.py

aria/core/AssignmentFilter.py

aria/core/Atom.py

aria/core/Calibrator.py

aria/core/Chain.py

aria/core/ChemicalShiftFilter.py

aria/core/ChemicalShiftList.py

aria/core/Cluster.py

aria/core/Contribution.py

aria/core/ContributionAssigner.py

aria/core/ConversionTable.py