New Mzalendo homepage layout

Closes #1528

Tested in Chrome, Firefox, and Opera Mini. Looks lovely! Thanks @wrightmartin for the wireframe and @dracos for some CSS advice!

![screen shot 2014-10-10 at 15 34 57](https://cloud.githubusercontent.com/assets/739624/4593903/a1badbd4-508a-11e4-92f0-962ac0504e27.png)


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