Issue #924 Update homepage to better reflect our projects.

1. Resized the penguin logo so main header text can fit in 2 lines.
2. "Get Help" box replaces "Attend events".
4. Added new outreach links + pictures.
3. Added Twitter follow button at bottom of page in blog widget.

Thanks Britta for making the mockup. 

Below is a screenshot of the new homepage: 
![924_new_homepage](https://f.cloud.github.com/assets/954858/2057257/1cab5d60-8b19-11e3-9abf-32bc4ceaaccf.png)