add test for modifying blank nodes retrieved from Linq

this should start passing once loading of SPARQL results is refactored
to retrieve whole graphs when resulting entity is a blank node
additional tests for selecting mutliple where some are blank
Fixes logical but when retrieving entitys sub property. In case this property was of IEntity type and this entity was an RDF blank node, no owning graph was loaded leaving the entity unhooked from it's parent entity's graph, which contained other triples describing other blanks that may have been related to that very blank node.
Fixes logical but when retrieving entitys sub property. In case this property was of IEntity type and this entity was an RDF blank node, no owning graph was loaded leaving the entity unhooked from it's parent entity's graph, which contained other triples describing other blanks that may have been related to that very blank node.
Merge branch 'master' of https://github.com/MakoLab/RomanticWeb into linq-blanks