Thanks to this registration to process_group_pid_set allows cleanup of test
suite too.

If something else is left behind, those are disconnected processes of test
suite itself, which shall be cleared in that one.

For now move supervisord_pid_file to global and calculate it "magically".
Thanks to this it is proven, that supervisord can be killed correctly.

Prepares for task cleanup on failure.

Test runner should not die because of any RPC-related failure.
Also, print a nice traceback of the error.

Also, don't name custom log files with a leading dot in partition's root.
This is reserved to supervisord logfiles. Follow (somewhat) the FHS and
put log files in testrunner partition's /var/log.

Original implementation was defining it globally, and applying it on the
first repository list entry.

between to test suite launch, it is not needed to keep
supervidor running. This allows to save memory usage

This will allows to use it for several different external method
calls

- a list of repositories to synchronize can be provided
- the first repository is used for software
- transfer project revision with string like
  [repo x]=[commit count x]-[hash x],[repo y]=[commit count y][hash y]
- change related to new structure :
  recipe slapos.recipe.erp5testnode is inside slapos.cookbook egg
- allow authentification setting for several repositories
- drop support for svn

- a list of repositories to synchronize can be provided
- the first repository is used for software
- transfer project revision with string like
  [repo x]=[commit count x]-[hash x],[repo y]=[commit count y][hash y]
- change related to new structure :
  recipe slapos.recipe.erp5testnode is inside slapos.cookbook egg
- allow authentification setting for several repositories
- drop support for svn

Also drop extras because of https://bugs.launchpad.net/zc.buildout/+bug/85604