This command adds a DarkBASIC Pro double
integer to the specified packet. Typically double integers are 8 bytes
in size and range from -9,223,372,036,854,775,808 to +9,223,372,036,854,775,807.
The data will be added starting at the cursor position and the cursor will be moved forward by the size of the data added.
long long int Packet: This is the packet that the command should use.
double integer: This is the data to be added.
0 if no error occurred.
-1 if an error occurred.
DBP