Recognition of projection based stereochemistry.

Change-Id: I449ccaaf5909efb1f45377c4391362b64140b15c
Signed-off-by: Egon Willighagen <egonw@users.sourceforge.net>
Release 1.5.9
Bumping version number, open for patches.
Minor correction to JavaDoc.
Merge remote-tracking branch 'upstream/master'