Use https for GitHub URL

Indiewebify.me complained that it couldn't fetch
http://github.com/chrisroos.
Link to GitHub from my homepage

While Indiewebify.me correctly parsed my /contact page and found my
GitHub profile, my GitHub profile links back to my homepage and not
/contact. Adding a link to GitHub on the homepage should solve that.

I had wanted the link to GitHub to appear below the blog posts but I
get some illegal nesting error when I try to do that.
Use rel=me to link to my contact page

I want to see if this'll allow me to use web sign-in without having
links to my profiles on my homepage, as per the relmeauth spec[1].

[1] http://microformats.org/wiki/relmeauth#users_with_separate_contact_pages
Revert "Use rel=me to link to my contact page"

This reverts commit 3dd4070399e533bdc58739f243306082a8d9da15.

It turns out that indieauth doesn't currently support this use[1] so
I'm reverting to link from my homepage only for now.

[1] https://github.com/aaronpk/IndieAuth/issues/48
Add post about exploring Google Location History