Rename bldr to loadstar
Make sure directory exists before writing file.
Expose fetchData, instead of store.
Display more useful error if file is not found.
Use key, not appGlobal when attaching to data.
polyfill path.isAbsolute (available in node 0.11)
Track external dependencies.
Resolve external dependencies relative to package base.

For example, if we have `loadstar.require(‘lodash’);`

Then, in package.json, we can have:

```
“loadstar”: {
  “dependencies”: { 
    “lodash”: “./dist/lodash.min.js”
  }
}
```

Which will resolve to node_modules/lodash/dist/lodash.min.js

An absolute path will be rooted at our project root:

```
“loadstar”: {
  “dependencies”: { 
    “lodash”: “/vendor/lodash-mine.js”
  }
}
```

If you put false as the value inside the dependencies
object, then no warning will be output. Use this
if you are building a library that has external dependencies,
and allow the user of your library to add the dependency.
Release 0.4.0 as loadstar
FIX: do not modify external sources.
Release 0.4.1: fix external source handling.