WIP: Rewrite in es6 to support nodejs and browsers

Only the memorystorage works for now, but this is to give an idea on how it would work To test:

1. Install rollup.js (the simplest to create the build file): $ npm install -g rollup
2. Update local packages $ npm install
3. Build the dist file for nodejs and browsers: $ rollup -c
4. Run the sample test for node: $ node examples/node.js