Subroutine:   COPYHEAD_LEVEL

Purpose:      Copies all header items which are located at a given
              level in the input set, to a given level in the
              output set, except for reserved keywords.

Category:     HEADER

File:         copyhead.c

Author:       Fred Lahuis

Use:          CALL COPYHEAD_LEVEL( INSET       INPUT char*(*)
                                   OUTSET      INPUT CHAR*(*)
                                   INLEVEL     INPUT integer
                                   OUTLEVEL    INPUT integer
                                  )

              INSET     input set
              OUTSET    output set
              INLEVEL   coordinate word of the level from which
                        the items are to be read
              OUTLEVEL  coordinate word of the level to which the
                        items are to be written.

Comments:     Reserved keywords are not copied.
              
Updates:      August 23 1991:    FL, Creation date.
              September 10 1991: FL, Copying of a maximum number of
                                     items at once added.
              September 19 1991: FL, Check on reserved header items 
                                     added.
              August 25 1993:    FL, Minor bug removed.