Clicking links navigates away from tutorial page

[bobhilt]

Repro:

1. https://github.com/chalmerlowe/intro_to_sprinting/blob/master/class_materials/installing_tools.md
2. click on "using conda" link.
3. navigates to link in same tab, which has further links that begin to wander farther from the tutorial.

Suggest:
Make (at least external) links open in new tab by default, which keeps the user oriented in the tutorial while exploring elsewhere.

[chalmerlowe]

Sounds good! This sounds like something that should be done universally.

[joeygrasso]

I could be wrong, but I don't think markdown supports opening a link in a new tab or window.
I don't think there is an equivalent to target="_blank"

[seawolf42]

@joeygrasso I believe you're right, you can't do that directly... however you can also inject raw HTML in .md, so a real link could be created in those cases.