#675 Hash coding of IStereoElements - ITetrahedralChirality

[John May]

feature/tetrahedral-stereoelement-hash

From commit 'Separate the implicit/explicit versions of butan-2-ol between files.'

Turns out it was quite easy to do. This patch allow one the hash generation to encode tetrahedral centres specified by the 'ITetrahedralChirality'. The generated hashes are the same as that when using 2D coordinates (shown in the HashCodeScenarios). I also made it forward compatible to check for the 'implicit' reference via using the central atom.

The code for IAtomParity would be the same - but we should probably convert anyone existing code using IAtomParity to ITetrahedralChirality (i.e. InChIToStructure).

[Egon Willighagen]

Same here. Generally looks more than OK, but mostly license/copyright headers missing.

[John May]

Okay add the headers with another commit.

[Egon Willighagen]

Thanks. Applied and pushed.