first up the version number
improvements to lib functions

* mkdir_p() accepts mode
* exec_command() and shell_command() return code
* unix_out() prints externally invoked commands
add ssh multiplexing to dsh
exec_command() may be run silent (redirect to devnull)

and run_with_nodename() gains a returncode
dsh can start/stop/check/exit multiplexing
added param control_persist
ssh muxing for dsh-pkg
unix_out() already done by run_with_nodename()
ssh muxing for synctool
undefined var 'ret'
rsync with ssh multiplexing
documented multiplexing
added security for control paths
Merge branch 'multiplex'

Added ssh multiplexing for lightning fast ssh connections.
Idea given by 'calind' at github in issue #33
updated Changelog