Added background images to dribbble and sprintly

Copied over the background-properties of the section above the removed footer to make it all look nicer on taller screens

#### How it looks

**Dribbble before:**
![dribbble before](https://f.cloud.github.com/assets/520420/590810/92ecf046-c9f0-11e2-947d-d989e6e35e88.png)
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**Dribbble after:**
![dribbble after](https://f.cloud.github.com/assets/520420/590816/bc372318-c9f0-11e2-8de9-52ddcb90a5e0.png)
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**Sprintly before:**
![sprintly before](https://f.cloud.github.com/assets/520420/590819/c744434e-c9f0-11e2-9951-7e893279f45a.png)
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**Sprintly after:**
![sprintly after](https://f.cloud.github.com/assets/520420/590821/d17b04ec-c9f0-11e2-8246-c9e1d9d1b193.png)