Writing and revision of CVE documentation for PE 2.7.2
Add new boilerplate text to redmine workflow doc

This describes the 'code insufficient' state, where a user
has submitted a patch and someone (PL or another user) found it
not to completely address the problem or regress on something.
WIP: best practices in examples

Bringing release notes over from wiki to docs
Creating a release notes page and supporting nav elements so we can deprecate the wiki release notes.
Changing release notes template to mitigate confusing nav sidebar shifts.
Fixit: Pointing to a better location for later PE release notes.
Merge branch 'master' of github.com:puppetlabs/puppet-docs into pe2.7.2
Added documentation for installer upgrade checking and how to disable it in answer file.
Fixit: Errant markdown in recently imported Puppet 2.7 release notes
Edits and revisions of CVE's based on feedback from Josh C.
Wiki Migration:  Release codenames
Update mcollective nav menu for new docs
Last few edits before deploying 2.7.2 docs.
Merge branch 'master' of github.com:puppetlabs/puppet-docs into pe2.7.2
Fixing a typo.
Release notes updates for 2.6.18, 2.7.21, 3.1.1