Function            color - make a single attribute

  Syntax              #include <video.h>
                      color(f,b)

  Prototype in        video.h

  Remarks             converts a color for a foreground and background
                      attribute in foreground format (0-15) to a single
                      byte.

                      This function is a macro.

  Return value        returns an attribute byte of foreground ORed with
                      the background shifted left 4 bits.