Add name translation for MetaList query results

closes #16
Use ResponseEvent => onImageRecieved

instead of NewDeviceEvent. This is cleaner and allows to delete the
IGTLQueryNode safely
(otherwise the node is still in the QueryWaitingQueue in the
ConnectorNode, and the dead address will segfault in the receive
loop).
Merge pull request #19 from ihnorton/bqn

GetImage: use descriptive image names from ImageMetaList