update configuration to allow the core/upgrade/install.php to have the
same read_timeout in nginx as it has in php execution time.
This should prevent the nginx timeout error when a upgrade takes longer
than 60 seconds (the deafult in nginx)
* adding devuan
* add devaun desc to README
make update and upgrade more noisy
correct path for devuan in pre-install
* some untested code for the source install - source installation is broken in Debian installation script and I have not debugged the problem. Focusing on the packaged version first.