CCPACSPositioning is not exposed to swig

[joergbrech]

from tixi3 import tixi3wrapper
from tigl3 import tigl3wrapper
import tigl3.configuration

# Create a handle to the tixi document
tixi_handle = tixi3wrapper.Tixi3()
tixi_handle.open("simpletest.cpacs.xml")

# get dihedral using TiXI
xpath = '/cpacs/vehicles/aircraft/model/wings/wing[1]/positionings/positioning[1]/dihedralAngle'
print(tixi_handle.getDoubleElement(xpath))

# get dihedral using TiGL
config_handle = tigl3wrapper.Tigl3()
config_handle.open(tixi_handle, "")
config_mgr = tigl3.configuration.CCPACSConfigurationManager_get_instance()
config = config_mgr.get_configuration(config_handle._handle.value)
wing = config.get_wing(1)
wing_uid = 'Wing'
help(wing.get_positionings()) # <-- no getter, i.e. wing.get_positionings().get_positioning(i) is not implemented in CCPACSPositionings
help(wing.get_positionings().get_positionings()) # <-- SwigPyObject, should be vector of unique_ptr to CCPACSPositioning

[joergbrech]

@merakulix and I discussed this and we prefer to implement getters in CCPACSPositionings for the cpacs traversal in Python. Exposing std::vector and std::unique_ptr via swig to Python adds an unnecessary level of complexity, see RISCSoftware/cpacs_tigl_gen#59.