URLs for dependencies?

I do mostly node development on Mac and Linux. Will URLs be supported for dependencies a la `npm` in package.json?

```
// get from the usual location (semver)
"My.Lib": "~4.0.0.0"

// get and build from git
"My.Lib": "git://github.com/mgutz/My.Lib#HEAD"

// get from local hacking directory
"My.Lib": "file://home/mgutz/src/My.Lib"
```
