Resolves #31
User perspective
Both commands, check and fix, now support to process multiple target files and folder. (For all given folders, recursively all files are processed. If you give a file directly and an (indirect) parent folder of it, the file is always only processed ones.)
Developer perspective
To extend also the lib crate interface, the CommandArgs struct get a second new function to create an instance with multiple targets. Furthermore, the renamed targets getter of the struct is now only visible inside the crate as there is no need to use it from the outside. (Assumption: Currently not used yet from the outside.)
Resolves #31
### User perspective
Both commands, `check` and `fix`, now support to process multiple target files and folder. (For all given folders, recursively all files are processed. If you give a file directly and an (indirect) parent folder of it, the file is always only processed ones.)
### Developer perspective
To extend also the lib crate interface, the `CommandArgs` struct get a second `new` function to create an instance with multiple targets. Furthermore, the renamed `targets` getter of the struct is now only visible inside the crate as there is no need to use it from the outside. (Assumption: Currently not used yet from the outside.)