New member *cmd_table is added in structure Monitor to avoid direct usage of
*mon_cmds. Now monitor have an associated command table, when global variable
*info_cmds is also discarded, structure Monitor would gain full control about
how to deal with user input.

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>