In addition, start ordering header file includes to be in more
consistent order: system header files, src/utils, src/*, same
directory as the *.c file.
Implements the Chargable-User-Identity (CUI), as defined in RFC 4372.
Option "-i" causes the eapol_test to send a NUL CUI - which is a request to
send a CUI back. Capital "-I" allows to specify the value of the CUI.
This has been defined for cases where the client wants to reauthenticate.
