Better supports for erb and blocks

I've realized I should change a lot of reference to erubis and other stuff, that can be tricky, so for now I'll go with the other solution you suggested: bound it to `cell`.
However, when I've a little more time to test it well, I think I will setup the standalone gem :+1: 

**Sorry, I've made a mistake, obviously this should merge into cell4's branch. Do you know how I can change or delete this?**