I believe it was said that Ti SDK 6.0.0+ came with full node support. This should include installation of npm modules as well. Sadly, a lot of modules are not passing the compilation process of titanium, because they do not follow a certain convention.
One of those error messages would be:
Create a package.json (regular npm setup) inside app/lib so the packages come available during runtime. Install for instance `mocha` (https://www.npmjs.com/package/mocha). There are many more packages that will fail the compilation process once installed into /app.
run `npm install` in this directory to install the module.
I recommend installing a lot of packages, and determine if they pass the Alloy compiler. Every compilation should pass.