This is a commit to add the following feature:

1) add gtm slave
2) add gtm proxy
3) add coordinator slave
4) add datanode slave

	modified:   config.c
	modified:   coord_cmd.c
	modified:   coord_cmd.h
	modified:   datanode_cmd.c
	modified:   datanode_cmd.h
	modified:   do_command.c
	modified:   gtm_cmd.c
	modified:   variables.c
	modified:   variables.h