Update thrisume blog post about Spacemacs

[StreakyCobra]

As @geo7 pointed out on gitter, trishume blog post about Spacemacs is highly ranked on Google results. Some users coming in the past to gitter were having questions/problems after having read this article because it starts to be outdated.

I wrote a mail to @trishume with some basic changes, asking him also to put a notice at the top saying that information can be outdated. He already did some modifications (thanks to him 👍) but there is still some parts that are not exact. He is open to PR as his blog is on github.

It would be nice to PR the changes needed to adapt the article to last version of Spacemacs.

[syl20bnr]

Good initiative 👍
I'll check it again when I can.

Thanks @trishume for keeping up to date the article, it is greatly appreciated!