refs #5162
- allow pagination and navigation partial helpers to have attributes passed through to them
- e.g. {{navigation header=true}} -> {{#if header}} will now work
- allows styling navigation to be done differently for different sections of the page
- properly create a data frame, and pass through "this" context
- means {{navigation header=true}} is the same as {{> navigation header=true navigation=@site.navigation}}
- our partial helpers, have the same behaviour exactly as if the partial was called directly
- this is additive, and improves behaviour
