The new option tells the checket to load the file in memory and look for
a comment line "# coding: <codec>". If found, the named codec is used
to decode the file before checking. This makes sense only if said codec
doesn't change the line numbers of the initial file. An example of such
codec is "spec" provided by the "Nose of Yeti" library:
https://github.com/delfick/nose-of-yeti
