Remove ConceptsResource::getConceptsByCriteria()
Add objects related to query management
QueryResult::getSize(): ret Long, not Integer
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Improve querytool api so as to support constraints

Also:
  - Refactored QueryResult.Status into the QueryStatus enum.
  - Made QueryDefinition and the classes that compose it immutable.
  - Added InvalidRequestException.
  - Declared that QueriesResource::runQuery() throws this new exception.