Release v2.1.2 : Port to Python 3

Full port to Python 3

What's Changed

• Release 2 0 by @pradal in #1
• Fix wrong setup.py by @pradal in #2
• Fix matplotlib deprecated import by @pradal in #3
• Add conda package to MTG by @pradal in #6
• Doc by @pradal in #9
• Raise an error when accessing to a vertex that is not in a MTG by @pradal in #13
• change a filter in python 2 > 3 by @pomme-abricot in #20
• port to python 3 by @fredboudon in #15
• Update the move to Python 3 by @pradal in #21
• Update Continuous Integration package by @pradal in #23
• OpenAlea Namespace by @pradal in #24
• Reactivate noarch package with the ability to generate egg package by @pradal in #25

New Contributors

• @pradal made their first contribution in #1
• @pomme-abricot made their first contribution in #20
• @fredboudon made their first contribution in #15

Full Changelog: https://github.com/openalea/mtg/commits/v2.1.2