Merge simplified euler to optic flow

doc/source/tests/index.rst

doc/source/tests/maths.rst

doc/source/tests/moving.rst

doc/source/tests/processing.rst

doc/source/tests/sensors.rst

doc/source/tutorials/01-building-arena.ipynb

doc/source/tutorials/02-recording-animal-trajectory.ipynb

doc/source/tutorials/02a-orientation-background.ipynb

doc/source/tutorials/02b-orientation-3markers.ipynb

doc/source/tutorials/02c-orientation-2markers.ipynb

doc/source/tutorials/03-rendering-along-trajectory.ipynb

doc/source/tutorials/04-error-propagation.ipynb

doc/source/tutorials/05-classification.ipynb

doc/source/tutorials/compound_eye.jpeg

doc/source/tutorials/database.rst

doc/source/tutorials/examples/blenddemo_beesampling.py

doc/source/tutorials/examples/blenddemo_cyberbee.py

doc/source/tutorials/index.rst

doc/source/tutorials/opticFlow_tutorial.ipynb

doc/source/tutorials/renderimage.rst