Update Julia by Example

[Nosferican]

No description provided.

[arnavs]

Can confirm that this is undeprecated. But I want to hold off on merging until we figure out a clean, permanent solution to the scoping issue Jesse mentioned in #39.

Additionally, I think this syntax:

using Pkg: add, installed
"Distributions" ∈ keys(installed()) || add("Distributions")

should either be explained or hidden. I think @jlperla's goal was to make these lectures similar to an Apple demo --- showing you no more than you need to get on board.

[jlperla]

Yeah. I am generally loathe to use anything relying on short circuiting logic at all. It is pretty advanced for new users, and even confusing for good programmers coming from many languages.

But I suspect that code is just temporary until we have the Manifest stuff working

[arnavs]

Reviewed above.