InitSerialNumberCode
procedure InitSerialNumberCode (const Key : TKey; Serial : LongInt; Expires : TDateTime; var Code : TCode);
InitSerialNumberCode creates and initializes a serial number code using Key, Serial, and Expires.
Serial is stored as part of the Code.
The resulting code is valid until the date stored in Expires is reached.
This routine is defined in the OnGuard unit. (as of 1.15 this routine has been moved to the OgUtil unit)