add support for fully automatic upgrades

The Upgrader avoids checking for upgrades on startup when it was just
upgraded. This avoids an upgrade loop if something goes wrong. One example
of something going wrong would be if the upgrade info file and the
distribution file get out of sync (or the distribution file is cached in
a proxy), so it thinks it has upgraded to a new version, but has really
not.

1 files changed, 0 insertions, 0 deletions

diff --git a/doc/assistant/upgradecomplete.png b/doc/assistant/upgradecomplete.png
new file mode 100644
index 000000000..3f8c7f3c2
--- /dev/null
+++ b/doc/assistant/upgradecomplete.png