VIVO-403 safeguards against duplicate context  node creation in migration
VIVO-388 fixes vivo:middleName migration bug
VIVO-476
Merge branch 'maint-rel-1.6' of https://github.com/vivo-project/VIVO into maint-rel-1.6
VIVO-493 hiding "has participant" / "participates in"
Merge branch 'maint-rel-1.6' of https://github.com/vivo-project/VIVO into maint-rel-1.6
VIVO-490 thank you very much and please tip your waitress
VIVO-492
Merge branch 'maint-rel-1.6' into develop