Adding Sheldon McKay
Adding John Corless
Adding Aaron Garoutte
Adding Arliss Collins
Adds several hyperlinks, and fixes one typo.
Blg post about job in TGAC
Merge pull request #504 from hlapp/patch-1

Adds several hyperlinks, and fixes one typo.
Updating Arliss Collins' bio
Merge branch 'tgacJob' of github.com:apawlik/site into apawlik-tgac-post
Merge branch 'master' of github.com:swcarpentry/site into apawlik-tgac-post
Job opening at TGAC