issue #9, save running config mechanism

the cli (in cmd_write_mem() ) creates the config dir now, if it
doesn't exist, with an appropiate message to the console.

 - separated defines for SW_CONFIG_ROOT and SW_CONFIG_FILE

 - it also aborts command when SW_CONFIG_ROOT is not a dir

Signed-off-by: Ion Dumitrache <gear@ines.ro>