New massive members of Cygnus OB2

We acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) under the grants AYA2012-39364-C02-01, AYA 2015-68012-C2-01 and Severo Ochoa SEV-2015-0548. A.S. also acknowledges support from MINECO through grants AYA2013-40 611-P and AYA2016-75 931-C2-2-P. AP and CBM acknowledge support from the Sonderforschungsbereich SFB 881 “The Milky Way System” (subproject B5) of the German Research Foundation (DFG).