(Feature Request) Use ES6 modules

The EcmaScript 2015 standard (ES6) introduced a module system, that allows for multiple JavaScript files to import from one another and build complex applications.

The latest version of most browsers support ES6 syntax, and even support using these modules without a compiler.

The first library we used for bundling modules in the NPM release of OpenFL was browserify, but circular references resulted in needing to remove features from the library. ES6 modules have better handling of cyclic dependencies, depending on the implementation. We use Webpack, and have no circular dependency issues. Being compatible with modern JavaScript toolchains also opens up a wide world of ways to mix/match/interact/expand on the codebase.

If Royale supported ES module output, we would gain support for using SWF assets, for granular code splitting, for many, many features "for free" from the NPM community, and make the cost of integrating ActionScript-based sources much lower in an NPM-based project.

No file, test, or entry point is named. Start by locating the NPM release bundling path and its browserify or Webpack configuration, then define the required ES module output, including the stated SWF asset and code-splitting use cases; done means Royale output can be consumed by modern JavaScript toolchains.

Written by the indexing model from the issue text.