Moving diff related columns into diff command, because they are not used
by any other command.

Also moving the column entry functions under generic one with baseline
as an exception.
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Reviewed-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-v58qfl75xkqojz54h1v5fy6p@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>