Release 1.20

• If benchexec --container is used, all code that is part of the tool-info module (as well as all processes started by it) are now run in a separate container with the same layout and restrictions as the run container.
  Note, however, that it is not the same container, so any modifications made by the tool-info module to files on disk are not visible in the runs!
  The test_tool_info utility also has gained a parameter --container for testing how a tool-info module behaves in a container.
• Nested containers are now supported.
  Due to a change to the internal implementation of the container mode, commands like the following succeed now:
  containerexec -- containerexec --hidden-dir /sys -- /bin/bash.
  (Some parts of /sys need to be excluded because of kernel limitations.)
  Note that nesting runexec or benchexec is still not supported, because nested cgroups are not implemented, so any cgroup-related features (resource limitations and measurements) are missing. But nesting containerexec and runexec --container (or vice-versa) now works.
• /etc/hostname in container now also shows the container's host name that exists since BenchExec 1.19.
• Change how CPUs with several NUMA nodes per CPU are handled:
  BenchExec will now treat each NUMA node like a separate CPU package and avoid creating runs that span several NUMA nodes. Thanks @alohamora!