- Add conversion for single character constants, offering
  to convert them characters or QLatin1Char.
- Offer conversions from character constants to string constants.
- Rewrite the WrapStringLiteral::Operation class such that it
  takes a mask of actions to perform which can be combined
  in arbitrary ways. Provide static convenience functions
  that can be used for the Translation/Objective C conversion
  as well.
- Move code outside class to reduce indentation.
- Use its functionality for the Translation/Objective C
  conversion as well, reducing redundant analysis/operation code.

Change-Id: If32c16a705cfc1cc20a48ab1c93b5053467d1749
Reviewed-by: Leandro Melo <leandro.melo@nokia.com>