Julia tutorials?

@sdrastro wrote some Julia tutorials that we might want to consider hosting on Learn:
https://github.com/lootie/Multitaper.jl/tree/master/Julia_quickstart 

They could probably use some re-organization and breaking up into ~3 tutorials. 

But, they are Jupyter notebooks so I don't think there's any technical reason why we couldn't host them, right? 
