v2.3.1

• Fixed fused ring numbering algorithm incorrectly numbering some ortho- and peri-fused fused systems involving 7-membered rings
• Support P-thio to indicate thiophosphate linkage
• Count of isotopic replacements no longer required if locants given
• Fixed bug where CIP algorithm could assign priorities to identical substituents
• Fixed "DL" before a substituent not assigning the substituted alpha-carbon as racemic stereo
• L-stereochemistry no longer assumed on semi-systematic glycine derivatives e.g. phenylglycine
• Fixed some cases where substituents like carbonyl should have been part of an implicitly bracketed section
• Fixed interpretation of leucinic acid and 3/4/5-pyrazolone