feat(ipython): represent objects using '__str__' rather than '__repr__'
requested to merge 167-proposal-to-use-__str__-or-ipython-s-_repr_pretty_-instead-of-having-user-targeted-strings-in into master
Description
Changes all __repr__ to __str__, and tell IPython to display the nice output
from __str__ except if it is not overwritten, in this case it would keep the
classic behaviour
Closes #167 (closed)