added isPartOf pending markup to all new terms. Removed duplicate label declarations and issue tag from the core terms whose domains are being extended.
added isPartOf pending markup to all new terms.
Removed duplicate label declarations and issue tag from the core
terms whose domains are being extended.

/cc #2419 @vtardif

schemaorg/schemaorg,schemaorg/schemaorg,vholland/schemaorg,schemaorg/schemaorg,schemaorg/schemaorg,vholland/schemaorg,vholland/schemaorg,schemaorg/schemaorg,vholland/schemaorg