Improve documentation of convenience layer

docs/_build/doctrees/EV3.doctree

docs/_build/doctrees/Motor.doctree

docs/_build/doctrees/Sensor.doctree

docs/_build/doctrees/environment.pickle

docs/_build/doctrees/examples.doctree

docs/_build/doctrees/index.doctree

docs/_build/doctrees/readme.doctree

docs/_build/doctrees/source.doctree

docs/_build/html/EV3.html

docs/_build/html/Motor.html

docs/_build/html/Sensor.html

docs/_build/html/_sources/examples.txt

docs/_build/html/_sources/index.txt

docs/_build/html/examples.html

docs/_build/html/index.html

docs/_build/html/searchindex.js

docs/_build/html/source.html

docs/_build/latex/Makefile

docs/_build/latex/MindstormsEV3Toolbox.aux

docs/_build/latex/MindstormsEV3Toolbox.idx