DRY up the team

**Goal**:
Make it very easy to add new team members (or teams) in the future

**The Changes**:
Instead of copying and pasting the markup and directly changing it there, you can now add (or move or remove) team members by changing a bit of YAML in a file called `teams.yml`

**Background**:
On a whim, I decided to try and DRY up the code used to display the team and its members. 

I used YAML as [accessible custom data in Jekyll](http://jekyllrb.com/docs/datafiles/) to hold information about each person on the team. It's presented in the view using the same bits of markup and some Liquid templating.

Everything to see is in the code and I'm open to suggestions.

**NOTE**: I tried my best to keep everyone's information the same and even tested all of the links, but I may have made a mistake here or there.

**Example**:
![teams_yml_-_stitchfix_github_io_-____work_stitchfix_stitchfix_github_io_](https://cloud.githubusercontent.com/assets/1062929/4570084/b64f04d8-4f56-11e4-8d07-5864a6c97ea8.png)


This particular nested if statement is here (LinkedIn) because some users have a nice clean public profile (so I could just pull the user name) and others have the old URL which couldn't be parsed the same way.