v2.9.8

• Fix 1e-10 which was invalidly converted to .e-9 (this only applied to 1e-10, 1e-100, etc and not to other numbers such as 1e-11 or 1e-9), fixes #339
• JS: remove the use of the nullish operator ?? which is not supported by IE, Android+Firefox, and Android+Opera, fixes #338
• JS: fix bug in merging var declarations, where partial merges resulted in duplicate assignments