Support for componentAttachment different than qb:Observation #100
Description
Some datasets (http://obeu.vse.cz/dump/eu_budget_2014_nomenclature.zip) and their DSDs (https://raw.githubusercontent.com/openbudgets/data-model/master/budget/eu-budget/eu-budget-dsd.ttl) use qb:componentAttachment qb:DataSet or qb:Slice and LDVMi does not support those yet.