* Enforce file permissions in case they've changed
* test behaviour for autofile
* use testify in tests and rename `fInf` to `fileInfo`
* return an error if file permissions have changed
- if we can't read the file, we'll still panic
* get rid of "github.com/pkg/errors" dependency
* address review comments:
- prefix instead of suffix
- add state to err and construct formatting in Error() method
* address review comments:
- move error to libs/errors
