Add a FlagCommand style syntax to YAMLCommand

Also 'yaml  unload'
and also 'yaml[name].read[x].as_list.escaped'
This update has been needed for quite a while!
Fix some minor YAML issues, update some meta

- Various YAML command updates based on auf's suggestions
- more tag grouping
Merge pull request #702 from mcmonkey4eva/master

Pull request for needed functionality