When the same inverse location problem was performed several times in
raw, the same result was added several times in the cache. This lead to
singular matrices being created as sample points were not independent.

The corresponding catch was already handled before.

The ParameterDriver class has been introduced in Orekit for
the orbit determination feature.

Replaced raw arrays with Stream instances to avoid giving access
to internal arrays.

This allows for example to retrieve the DEM elevation for a
latitude/longitude pair.