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**Conflict of Interest Statement:** The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

The reviewer PN and handling Editor declared their shared affiliation.

Copyright © 2018 Baveye, Otten, Kravchenko, Balseiro-Romero, Beckers, Chalhoub, Darnault, Eickhorst, Garnier, Hapca, Kiranyaz, Monga, Mueller, Nunan, Pot, Schlüter, Schmidt and Vogel. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.