AC-FOVE: code refactoring for AggregationParfactor (split)

* Migration to JUnit version 4.11
* AggParfactor: split method
* AggSplitResult: added static factory
* StdParfactor: made builder more consistent
* Factor: correction in constant parfactor creation, equals() does
consider BigDecimal's scale when comparing values
* Tuple: added static factory
* UnconstrainedMarginal: replaced StdPrv with Prv
* Binding: method to convert to inequality constraint
* Substitution: has() method
* Lists: new methods to create and compare lists
* Sandbox: cleaning
* AggParfactorTest: tests for split

The biggest addition is the split method bundled with a new technique
to make tests, using advanced features from JUnit. Test code is
significantly shorter and more flexible.