Update to #59 regarding the suggestion by shane-axiom.
Now the SOS uses org.n52.sos.ds.Datasource property to load the defined class, e.g. org.n52.sos.ds.datasource.PostgresDatasource, in the Configurator and call the getter for ConnectionProviderIdentificator and DatasourceDaoIdentifier.
Merge pull request #61 from CarstenHollmann/update/datasource_dependent_dao_loading

Update to #59 regarding the suggestion by shane-axiom.