execute take command as string
add node class
- node class
- ssh_it/mpi_it to decorate exe() method
- return stdout in scratch functions
- add scratch_du to return disk usage for scratch directory
- add free scratch directory option @rtm_launch
move node_manage in directory
add __init__.py to node_manage
not print command to execute
change others for node_manage package
Merge branch 'iss11_cmd_decorator'

Conflicts:
	src/node_manage.py