Test notebooks with nbmake

[Mec-iS]

Notebooks seem to have some problems with imports, when I tried to run pytest --nbmake examples/:

examples/ex0_0.ipynb .                                                                                                                                                                           
examples/ex1_0.ipynb F                                                                                                                                                                           
examples/ex1_1.ipynb F                                                                                                                                                                           
examples/ex2_0.ipynb F                                                                                                                                                                          
examples/ex3_0.ipynb .                                                                                                                                                                           
examples/ex4_0.ipynb .                                                                                                                                                                           
examples/ex5_0.ipynb F                                                                                                                                                                           
examples/ex6_0.ipynb .                                                                                                                                                                           
examples/ex6_1.ipynb .                                                                                                                                                                           
examples/ex7_0.ipynb .                                                                                                                                                                           
examples/ex7_1.ipynb .                                                                                                                                                                           
examples/ex8_0.ipynb .   

In order of failure:

AttributeError: 'str' object has no attribute 'decode'
ModuleNotFoundError: No module named 'rdflib_jsonld.serializer'
ModuleNotFoundError: No module named 'rdflib_jsonld.serializer'
ModuleNotFoundError: No module named 'owlrl.OWL'

[ceteri]

Many thanks @Mec-iS , nice work!!