use consolidate to make template engine configurable

Step 1 in making the template engine configurable, use [consolidate.js](https://github.com/visionmedia/consolidate.js). I don't really like how the file extensions are named now, with some as `.html` and others as `.jade`. Need to think on that topic a little more. Might make sense to update the directory structure to split the file types.

@lirantal could be good to give `swig` a try instead of `jade`, as that might help with the extension problem.