Tabs inside Panel

Hi @artf, As you must know, at my company we are creating a product based on GrapesJS. We are trying to keep as close as possible from GrapesJS core. As developers we are trying our best to not create a fork from GrapesJS and keep contributing back to the repo. Now, we have a new feature to create and we would like to know if it's interesting for GrapesJS. We want to add tabs inside the blocks panel. It's works like the categories, they serve to group a specific set of blocks. Something like that <img width="253" alt="captura de tela 2017-11-09 as 15 55 03" src="https://user-images.githubuser...