Implement Lipinski descriptors and checker

[mkviatkovskii]

There is famous Lipinski's rule of five, that allows to quickly estimate "druglikeliness" of the molecule.

We need to implement method that checks if a compound satisfies all 5 criterias and return boolean value. Also there are additional Lipinski descriptors that could be used in predicting molecular properties:

1. Ratio of SP3 hybridized carbons.
2. Number of aliphatic cycles (cycles that contain non-aromatic bonds).
3. Number of aliphatic heterocycles (cycles that contain non-aromatic bonds and non-carbon atoms).
4. Number of aromatic rings.

We need to implement this decriptors and add unit tests for them.

[MysterionRise]

@mkviatkovskii @suppnova are we planning to have it in Indigo API or just only in Python?

[mkviatkovskii]

@MysterionRise we plan to move this functionality to Indigo C++ core later.