Use a command group 'presto' with subcommands instead of individual
commands with 'presto_' prefix.
The old commands are still available for backward compatibility but
marked as deprecated.
Change-Id: I883d8d87fd457d29cee8d12cd80f2e6c405e8f42
Signed-off-by: Marc Schink <dev@zapb.de>
Reviewed-on: http://openocd.zylin.com/6390
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>