Support for @@render tag

[seemantr]

@FransBouma First of all thanks a lot for creating DocNet. It is one of those things which I always wanted to do but could never get around to doing it. This is massively helpful. I am moving all my documentation from node.js assemble based website to DocNet. While doing so I am facing two limitation:

1. Support for include tag: This was easy and I have submitted a PR to do this.
2. Support for render tag: A render tag could be used as below:

@@render(<path to handlebar template>, <path to JSON file containing the data for the template>)

The above will allow users to auto generate portions of the documentation. For me the use case is to document models of REST end point. I have the specification available in Swagger format. I want to embed the models in documentation using the above approach. This can also be used to generate complex structures like tables etc in docs which is not directly possible with markdown.

Initially I wrote a F# script to do so but now I wanted to check with you, if you would be interested in such a feature? If yes then I can send a PR :-).

[FransBouma]

Glad it's helpful to others too!

@@render sounds nice. Looking forward! I'll have some time tomorrow (sunday) to look at your PRs and will merge them if there are no issues :)