- This function already expects these arguments not to be null pointers,
doesn't validate them and just dereference them.
- In order to make this explicit and enforced by the compiler, they're
now passed as references.
- Renamed Transformation::evaluate to Transformation::transform to avoid
confusion with Action's overload methods.
- Updated Transformation::transform signature to receive the value by
reference and perform the transformation inline, if possible.
- Some transformations still need to use a temporary std::string to
perform their work, and then copy the result back.
- Made Transformation::transform methods const and updated Transaction
parameter to be const.
- Transaction parameter could not be removed because it's used by just
a single transformation, UrlDecodeUni.
- Removed std::string Action::evaluate(const std::string &exp,
Transaction *transaction); which was only implemented by
Transformation but was not used from the base class, but only after
downcasting to Transformation, so it can just be declared there (and
not pollute other actions with a default member implementation -that
does nothing- which is never called).
