Merge pull request #16806 from s0undt3ch/2014.7

Reuse `_check_cache_minions` in `_check_grain_pcre_minions`.
Normalize release notes with develop branch
Added versionadded and versionchanged directives to Reactor docs

Also reworded and cross-linked the client interfaces docs.
Merge pull request #16822 from whiteinge/doc-reactor-changes

Added versionadded and versionchanged directives to Reactor docs
Don't let YAML have a newline party

YAML thought it would be super-helpful to break up a long string into
newlines. It was not that helpful.

Fixes #16413
Merge pull request #16824 from cachedout/issue_16413

Don't let YAML have a newline party
Return empty dict for list_pkgs(purge_desired=True) with macports

This fixes #16828
Clarify a couple links in the docs
Add notice of new packages for Helium release
Improve wording of RPM changes in helium release notes
Merge pull request #16846 from terminalmage/clarify-docs

Clarify a couple links in the docs
Add missing import
Merge pull request #16852 from s0undt3ch/2014.7

Add missing import
Merge pull request #16848 from terminalmage/helium-rpm-notice

Add notice of new packages for Helium release
Merge pull request #16805 from thatch45/agg_doc

fix docs for mod_aggregate per #16575
Merge pull request #16836 from opdude/2014.7

Return empty dict for list_pkgs(purge_desired=True) with macports
Fix MySQL master job cache

Conflicts:
	salt/returners/mysql.py
Merge pull request #16859 from cachedout/issue_15719

Fix MySQL master job cache
update raet intro
Redirect tot he correct page