fix sign position when padding character is 0 and the sign specifier is implicit (i.e. negative args)
fix sign position when padding character is 0 and the sign specifier is implicit (i.e. negative args)

GerHobbelt/sprintf.js,marob/sprintf.js,ychbcdq/sprintf.js,litmit/sprintf.js,Vreasy/sprintf.js,ychbcdq/sprintf.js,alexei/sprintf.js,andrasq/sprintf.js,Vreasy/sprintf.js,marob/sprintf.js,andrasq/sprintf.js,GerHobbelt/sprintf.js