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#692 SDF file atom parity calculated incorrectly when Hs involved
From the MDL specs:
"Number the atoms surrounding the stereo center with 1, 2, 3, and 4 in order of increasing atom number (position in the atom block) (a hydrogen atom should be considered the highest numbered atom, in this case atom 4). View the center from a position such that the bond connecting the highest-numbered atom (4) projects behind the plane formed by atoms 1, 2, and 3."
I don't think I handled hydrogens as described here.
Following discussion with WDI on shapado (http://blueobelisk.shapado.com/questions/has-anyone-got-experience-of-round-tripping-2d-sdf-smiles-sdf-and-its-effect-on-stereochemistry) and testing with Isis/Draw and Symyx Draw, it seems that both explicit and implicit hydrogens should always be considered the highest priority atoms if present.