Add access to the intersection algorithm Id

The getAlgorithm give the DEM intersection algorithm class. In some case, for instance, if a configuration file defines the way Rugged must be initialized, we may need to check the algorithm used. The enum AlgorithmId provides the right information but is not accessible through a rugged instance.

added Enhancement label

mentioned in commit f4a09c22

mentioned in merge request !2 (merged)

closed