Add OntologyTerm::getMetadata()
Fix char used for VisualAttributes.LEAF
Remove ConceptsResource::getConceptsByCriteria()
Add objects related to query management
QueryResult::getSize(): ret Long, not Integer
Add comment
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.
Excep. on bad arg to ConstraintByValue::forValue()
Add two methods to QueriesResource

These are:
  - QueryResult getQueryResultFromId(Long id)
  - QueryDefinition getQueryDefinitionForResult(QueryResult result)

See their Javadoc blocks for more information.
Annotate QueryDefinition with @EqualsAndHashCode