adjust expr_value() for RefData containing a single path.
adjust project data creation for RefData which only contains one path.
adjust unit tests on RefData to structure modification
adjust structure of Parameter and Service objects

- argpos, format, paramfile can be in any parameter of a Program
  (not only an Input)
- ctrls can be in any parameter of a Service
  (not only an Input)
- create new methods to take this into account:
  Service.parameters_list(), Program.parameters_list_by_argpos()
adjust Service unit tests to new Service structure.