New feature (fix for someone...): don't erase user's home if the computer crashes or reboots during the exam.
The user's home is erased (if required) only when the exam mode starts the first time.

Added esamesync-esame.service to graphical.target requirements, so the boot process stops if the master server is not reachable.

Otherwise we would get something like this:

  useradd: user 'rdesktop' already exists
  Error creating user rdesktop
  User rdesktop was created

Removed esame-get-config-boot.service as a requirement from some services (it is not needed anymore as esame-configurator target is reached before any other target at boot time).

That's where we run rsync for what's needed for the esame profiles.

Users added:
-esamesync
-esame
-moodle
-rdesktop

Directory created:
-/opt/esame

Fix: if the web service does not reply on machine boot, try 5 times then switch to graphical target.
If the WS does not reply when the machine is already in some exam mode or normal, do nothing.

Added warning and abort installation if the argument is 'v1.0' as the old installation procedure is different.