Added scatter series

That's interesting because I originally had this defaulting to 3 but I thought it looked too fat.  How about 2 as a default?  What  do you reckon?

**Size 1**
![image](https://cloud.githubusercontent.com/assets/4106217/3524320/74c2ec6a-0766-11e4-9a2e-c10f6b48a16c.png)

**Size 2**
![image](https://cloud.githubusercontent.com/assets/4106217/3524338/a9ba008e-0766-11e4-86c6-daa3a844adee.png)

**Size 3**
![image](https://cloud.githubusercontent.com/assets/4106217/3524345/b98bf044-0766-11e4-9a2e-bde54efad6c3.png)