Style tiles

# What's changed

* Alerts now appear underneath each other (they were overlapping before), and while doing so, don't upset the zen of the front page.
![screenshot 2014-10-03 14 09 31](https://cloud.githubusercontent.com/assets/485583/4502704/47a90bca-4acc-11e4-9947-f7bd7a985146.png)
* General cleaning up of styles, fixed the mis-alignment reported in #171. Closes #171 for now, because guide design is still being talked about pretty heavily.
* Added gradients shown in create guide designs to the actual design.

# What's next
* Starting to apply some of the style designs talked about in [guides conversations](https://www.loomio.org/d/iHfFyrsk/growing-guides-interface). Going to go for a mix of @ghislaineguerin and the original styles, probably leaning heavily on the visual style of her mobile designs. Onwards the march of MVP!