Use the newer `transformers` instead of the deprecated `consolidate-build`

I'm about to deprecate `consolidate-build` in favor of the newer `transformers`.  It comes with:

 - an optional promise based API
 - additional transformations (such as `cson`
 - magnification for JavaScript, CSS and JSON
 - better error handling when appropriate engine is not installed
 - output-format listings ('xml', 'css', 'js', 'json' or 'text')
 - optional synchronous rendering where possible

I'm actively watching `consolidate` now and will continue to add new template libraries from `consolidate` but by not being tied to using it as a dependency I can more quickly fix failings in its implementations.