Added --pillar-root option

Complement to --file-root option added in
abc240f7ba006f35d7f5463db54ba2aefcdde106
Added warning about * default to cron docs
quick fix to the iptables docs to show that set_policy is for the default rule on a chain
updated FAQ.
updated to faq file to reword backwards compatibility
Add C. R. to AUTHORS file.
Merge remote branch 'upstream/develop' into develop
added a new tutorial based around bootstrap-salt
Minor spelling fix

s/is not know'/is not known'/
Merge pull request #8548 from terminalmage/quickfix

Minor spelling fix
support user-defined chain in salt iptables moudle
support user-defined chain in salt iptables state module
Quiet down Yum's logging. Fixes #3855.

Salt does not need any of `sys.stdout`, `sys.stderr` and `syslog` logging handlers which are configured by Yum, specially because we're using Yum as an API, not as another CLI tool. Any logging will go through salt's logging handlers.
Just set the levels as the Yum package does.
Merge pull request #8551 from s0undt3ch/hotfix/quiet-yum-logging

Quiet down Yum's logging. Fixes #3855.
Make sure that an iterable is available. Fixes #8556.
Document that Raven is a required dependency. Fixes #8557.
Gracefully handle certain bad yaml conf files.

Parsing a conf file as valid yaml might still yield something other than
a dictionary, which is required. So check for that case, log an error,
and continue the same way that an invalid yaml conf file would be handled.
Merge pull request #8492 from rca/salt_local_pillar_root_option

Added --pillar-root option
Merge pull request #8496 from duk3luk3/docfixes

Added warning about * default to cron docs