This switches to the 0.11 release branch (which took years to get
officially stable, although the release candidates were completely
usable).
changes:
-many bugfixes
-added some command line options to tools
-improved logging
0.11 is compatible to 0.10 -- if 0.11 programs are used in a client
setup installed by 0.10 a script should be modified to avoid spurious
email warnings -- see the release notes