Create/Write/Delete relationships

[ahri]

Need to be able to create and destroy relationships, the the relationship aspect of TLO will be feature-complete.

Create:
TLORelationship::newObject($relationship, TLO $one, TLO $many)

Write:
TLORelationship->write()

Delete:
TLORelationship->delete()

[ahri]

Add create/write/delete for relationships. Closed by 733c68d