question numbers expander

Expand question number lists:
e.g. before: 1aiii,biii,2aiv,biv,3aii,bii,cii,4a,bii,civ
e.g. after: 1ai,1aii,1aiii,1bi,1bii,1biii,2ai,2aii,2aiii,2aiv,2bi,2bii,2biii,2biv,3ai,3aii,3bi,3bii,3ci,3cii,4a,4bi,4bii,4ci,4cii,4ciii,4civ