CountStereocenters does not include non-resolved stereocenters

**Steps to Reproduce**
Simple Winforms application written in C#
`IndigoObject mol = indigo.loadMolecule("ClC(Br)CC");
int nstereo = mol.countStereocenters();
Console.WriteLine("Stereo = " + nstereo);`

**Expected behavior**
Would expect the unresolved chiral centre to be counted (Stereo = 1)

**Actual behavior**
Result is: Stereo = 0

**Indigo version**
Indigo 1.12.0

**Additional context**
This has been the behaviour since the earliest versions of Indigo. Chrial centers are only counted if they have a wedge or hash bond (or SMILES @/@@). If backward compatibility is required, perhaps a new method could be introduced? E.g. mol.countChiralCenters()