This PR is the jessie version of the changes I have been working on.
For ease of review it does not contain all the debug prints, which I have moved to a separate PR.
The version we have tested combines both.
The changes are:
launch the splash without adding a monitor
set the app name of the splash so it writes to a separate log file
make the install* functions call relaunch and return false, instead of raising the exception there.
make the 4.1 scenario raise an exception instead of calling progress.relaunch(), since it will be ignored if it is not in the right thread.
make the scenario call apt-get update as a script instead of inside python (not sure this was actually necessary, but we tested it)
This PR is the jessie version of the changes I have been working on. For ease of review it does not contain all the debug prints, which I have moved to a separate PR. The version we have tested combines both. The changes are: