Refactor the management of uncertain arity due to possible aggregates
Moved IMDBTest to Ontop-test
Sum() type should not be hardcoded to xsd:double. Other operator types are still hardcoded.
Type pushing up now supports aggregation. SPARQL compliance test added
Merge branch 'feature/aggregates2' into feature/aggregate-order2
BUGFIX: unappropriate sort of atom arguments
SQLGenerator.getTypeColumnForSELECT() refactored. SPARQL 1.1 Aggregation compliance improved.
Merge branch 'feature/aggregate-order2' into feature/aggregates2

Conflicts:
	quest-owlapi3/src/test/java/org/semanticweb/ontop/obda/ImdbTestPostgres.java
	quest-test/src/test/java/org/semanticweb/ontop/obda/ImdbTestPostgres.java
	quest-test/src/test/java/org/semanticweb/ontop/sesame/tests/general/ImdbTestPostgres.java