add initial sphinx doc setup.

docs/Makefile

docs/source/README.md

docs/source/conf.py

docs/source/index.rst

docs/source/modules.rst

docs/source/phasecalculator.analysis.rst

docs/source/phasecalculator.classes.rst

docs/source/phasecalculator.io.rst

docs/source/phasecalculator.rst

docs/source/phasecalculator.runners.rst

docs/source/phasecalculator.test.analysistest.rst

docs/source/phasecalculator.test.classestest.rst

docs/source/phasecalculator.test.iotest.rst

docs/source/phasecalculator.test.rst

docs/source/phasecalculator.test.runnerstest.rst