-----------
- fix issue193: Remove ``--pre`` from the default ``install_command``; by
default tox will now only install final releases from PyPI for unpinned
dependencies. Use ``pip_pre = true`` in a testenv or the ``--pre``
command-line option to restore the previous behavior.
- fix issue199: fill resultlog structure ahead of virtualenv creation
- refine determination if we run from Jenkins, thanks Borge Lanes.
- echo output to stdout when ``--report-json`` is used
- fix issue11: add a ``skip_install`` per-testenv setting which
prevents the installation of a package. Thanks Julian Krause.
- fix issue124: ignore command exit codes; when a command has a "-" prefix,
tox will ignore the exit code of that command
- fix issue198: fix broken envlist settings, e.g. {py26,py27}{-lint,}
- fix issue191: lessen factor-use checks