mount /tmp in tmpfs to allow to switch the root fs in RO
Revert "mount /tmp in tmpfs to allow to switch the root fs in RO"

This reverts commit f620390721e20277220893bff6a92b77232dcf29.
mount /tmp in tmpfs and the root fs in RO
Mount src and dest partitions in /tmp instead of HOME. Thanks to Rémi Laurent.
assume the permissions of the home directory are correct. Allows us to have the root FS RO
append .txt to the log files. Make it easyer to open on Windows.
Merge branch 'dev'

* add support of root FS mounted RO
* append txt to the log files