refactor: eliminate ^{s,b,f} hungarian notation (#36)

Except for:
- `sOut`, for backwards compatibility, since it's included in public API

Via VSCode find and replace of:

- patt: `\b[bs](?!File)([A-Z]\w+)(?<!sOut)\b`
  with: `\l$1`
- patt: `\b[bs]File([A-Z]\w+)(?<!sOut)\b`
  with: `fileName$1`
- patt: `sFile`
  with: `fname`
- patt: `\bf([A-Z]\w+)\b`
  with: `file$1`

Author: vergenzt