Make this auto rebase-able on brix/crypto-js

[paviad]

One of the big arguments against adopting this library is that it has "less eyes" on it

I see that you have invested a lot of work into converting the original library to ES6 however it is not trivial to "rebase" this fork on changes upstream.

My suggestion is to split the conversion process into two distinct steps that will enable easier rebasing:

1. Move all code that does not change from inside the existing source files to other files, agnostic of the module system.
2. Complete the migration to ES6 based on that.

Does that sound feasible?