I normally change the libraries with Grunt, but here I want to provide a simple self-contained solution.

This is what I see: if I use ``paths.handlebars`` (lowercase), then ``r.j`` still uses the full HBS. If I use ``paths.Handlebars``, then the projects does not build, because ``r.js`` needs the full HBS at compile time, and the path is overwritten. This is why I added onBuildWrite to swap the runtime code at the en of the compilation.

Try it with the example:
- no path, onBuildWrite -> main.js is 12.8 KB
- paths.handlebars -> man.js is 72.9 KB
- paths.Handlebars -> does not compile

Bare with me, I really want to get to the bottom of this. I don't like shims and manipulations like onBuildWrite either!