Fixed header inheritance routine in order to not override fields which exist in original header (Issue-47)
Fixed header inheritance routine in order to not override fields which exist in original header (Issue-47)

Broken since r846
pgaval/unimrcp,andrenatal/unimrcp,pgaval/unimrcp,MattRiddell/unimrcp,AaronZhangL/unimrcp,AaronZhangL/unimrcp,andrenatal/unimrcp,MattRiddell/unimrcp,andrenatal/unimrcp,AaronZhangL/unimrcp,MattRiddell/unimrcp,pgaval/unimrcp