Final hessian calculation gives wrong degeneracies

[oboril]

Describe the bug
When using the --prop hess option, the final ensamble has incorrect degeneracies. It seems like the final conformers from the conformer search are passed to the hessian calculation without any degeneracy information (or all degeneracy = 1).

To Reproduce
CREST 3.0.2, xtb 6.6.1 (8d0f1dd)

Command: crest xtb.mol --gfnff --prop hess -T 8

xtb.mol:

Estimated minimal energy conformer (MMFF94 E: 2.79 kcal/mol)
     RDKit          3D

  6  5  0  0  0  0  0  0  0  0999 V2000
   -0.3711   -0.0008   -0.0089 C   0  0  0  0  0  0  0  0  0  0  0  0
    0.9238   -0.5655   -0.1011 O   0  0  0  0  0  0  0  0  0  0  0  0
   -0.5205    0.4087    0.9932 H   0  0  0  0  0  0  0  0  0  0  0  0
   -1.1131   -0.7807   -0.1956 H   0  0  0  0  0  0  0  0  0  0  0  0
   -0.4794    0.7886   -0.7566 H   0  0  0  0  0  0  0  0  0  0  0  0
    1.5603    0.1496    0.0690 H   0  0  0  0  0  0  0  0  0  0  0  0
  1  2  1  0
  1  3  1  0
  1  4  1  0
  1  5  1  0
  2  6  1  0
M  END

Output:

[...]
--------------------------
 Final Ensemble Information
 --------------------------
[...]
 total number unique points considered further :           3
       Erel/kcal        Etot weight/tot  conformer     set   degen     origin
       1   0.000    -0.76090    0.33334    1.00000       1       3
       2   0.000    -0.76090    0.33333
       3   0.000    -0.76090    0.33333
T /K                                  :   298.15
E lowest                              :    -0.76090
ensemble average energy (kcal)        :    0.000
ensemble entropy (J/mol K, cal/mol K) :    9.134    2.183
ensemble free energy (kcal/mol)       :   -0.651
population of lowest in %             :  100.000
 number of unique conformers for further calc            1
 list of relative energies saved as "crest.energies"

******************************************************************************************
**                     P R O P E R T Y   C A L C U L A T I O N                          **
******************************************************************************************
 writing TMPCONF* Dirs from file "crest_conformers.xyz" ... done.
 ---------------------------------------
 Hessian calculations for all conformers
 ---------------------------------------
[...]
 number of doubles removed by rot/RMSD         :           0
 total number unique points considered further :           1
       Erel/kcal        Etot weight/tot  conformer     set   degen     origin
       1   0.000    -0.73438    1.00000    1.00000       1       1     
T /K                                  :   298.15
E lowest                              :    -0.73438
ensemble average energy (kcal)        :    0.000
ensemble entropy (J/mol K, cal/mol K) :   -0.000   -0.000
ensemble free energy (kcal/mol)       :    0.000
population of lowest in %             :  100.000
 number of unique conformers for further calc            1
 list of relative energies saved as "crest.energies"

The degeneracy clearly does not propagate to the Hessian calculation, nor to the ensable calculation. For example, entropy should be RTln(3) = 9.1 J/mol/K as in the initial block, but the Hessian block shows entropy to be 0.

[pprcht]

The final calculation that can be selected with -prop refers to the crest_conformers.xyz file, which does not have the rotamers and hence no degeneracy info. Internally, the degeneracy info is not book-kept, and there is no intention to propagate all information to the -prop run mode.
At some point the -prop routines will be revised to use the newer tblite routines rather than the xtb binary, maybe I will change this printout in that revision.