Remove dependencies to nodejs pkgs so no extra config needed in browser

[clostao]

Currently, for using the package in the browser is needed this webpack setup.

The idea is remove this requirement so the package as plug&play as posible.

[clostao]

I've separated the main file of the package: One for nodejs and the other for browser.

This is a step towards solving this issue though it require to solve a problem with 'crypto' module not being available in browser enviroments.