IsDaysCodeValid
function IsDaysCodeValid (const Key : TKey; const Code : TCode) : Boolean;

IsDaysCodeValid returns true if Code is a valid days code, otherwise false.

Key must be the same key that was used to create the code or the code is considered invalid.

This routine is defined in the OnGuard unit. (as of 1.15 this routine has been moved to the OgUtil unit)