Initial working version
strip non-digit, non-alpha characters, allow for multiple delimiting characters
Convert also Unknown PGN
Merge @tkurki changes, but:
- Make camelization dependent on new flags -camel or -upper-camel.
- Fix camelization of repeating fields.
Don't set id, but generate

 "CamelCaseDescription":{ .... }

for each PGN when -camel or -upper-camel is generated.