Do not publish library as minified browserify bundle

[nwronski]

Instead of publishing this module on npm as a browserified and minified bundle, I want to publish the ES2015 code in src/ and the transpiled ES5 code in lib/ and leave it up to the end user to decide if they want to browserify or minify the library.

If the stream transform stuff makes it into v1.0.0 along with these changes then this would also allow a shim file to be specified so that the node stream library isn't included in a browserified version of this module. The configuration would be defined in package.json as:

{
  "map": {
    "./lib/streaming.js": {
      "browser": "./lib/streaming-shim.js"
    }
  }
}