Documentation
Remove obsolete parts
Rename approveRelation to approve
Fine grain pass control for fragments.

From now, pass is decided on three levels:
- relation: whether to handle given relation
- value: whether to handle given object value of a relatin
- assignment: whethern to handle an object that has subject object
  assigned as value to one of its relations
Update dependencies
Easier customization of pass resolvers
Be relaxed about deletion of not added fragment