hpo.py fixed zero denominator error on https://uclex.cs.ucl.ac.uk/phenogenon_json/HP:3000050
hpo.py fixed zero denominator error on https://uclex.cs.ucl.ac.uk/phenogenon_json/HP:3000050

pontikos/phenopolis,phenopolis/phenopolis,Withington/phenopolis,pontikos/phenopolis,pontikos/phenopolis,pontikos/phenopolis,pontikos/phenopolis,Withington/phenopolis,phenopolis/phenopolis,logust79/phenopolis,phenopolis/phenopolis,Withington/phenopolis,logust79/phenopolis,Withington/phenopolis,phenopolis/phenopolis,logust79/phenopolis,logust79/phenopolis