Updated documentation.

docs/components.graffle

docs/components.png

docs/conf.py

docs/data.png

docs/index.rst

docs/introduction.rst

docs/proc.png

docs/process.png

docs/setup.md

nomad/api.py

nomad/data.py

nomad/processing/__init__.py

nomad/processing/handler.py

nomad/processing/handlerdaemon.py

nomad/processing/state.py

nomad/processing/tasks.py

tests/test_processing.py