Fixes for broken links & dead link detection script

[ChildishGiant]

I've made a python script to detect possible down links and gone through all the ones it's picked up and fixed them all. I marked all the links that are down with siteDown: true and fixed two links that seem to have moved Generative Plants (2016-11-22-generative-plants.md) and CodeSlide ( 2017-03-28-codeslide.md). I'm relatively new to PRs so if you can, I won't mind if you don't want the script and just take 1869f3971bc52a6f13282a6664e61bcdb4360109

This'll close #314

[tholman]

I love it!, Could we perhaps put the sitedown part into a gist or something separate that we can reference in the readme ... Its awesome, but I feel a little weird adding a script onto the site that people may not understand/open to interpretation.

[ChildishGiant]

I think that'd make more sense, the only issue I guess is that the script has to be run in situ since it's using the markdown files.

[Achiria]

Any update on this? Hold off on the script if needed, but the links should be fixed.

[ChildishGiant]

See #316