All trails but gallery trails have borders between them

On fronts and read-more lists of trails, there was no border between some of the trails.

## Before
![screen shot 2013-07-16 at 11 51 12](https://f.cloud.github.com/assets/85783/804200/1ec031fc-ee07-11e2-9de3-081ab28e64fd.PNG)

## After
![screen shot 2013-07-16 at 12 04 49](https://f.cloud.github.com/assets/85783/804218/98bdffca-ee07-11e2-979e-c0031ff5c96c.PNG)


## Known issue
When an adslot div "ad-slot-middle-banner-ad" is included between two trails, there is no border between trails. Btw this should be addressed, as a `div` cannot be direct child of a `ul`.
On this screenshot, there is no border between the first trail and second trail because of this.
![screen shot 2013-07-16 at 12 03 13](https://f.cloud.github.com/assets/85783/804209/7c47bac0-ee07-11e2-9c62-1a9b37c8c9c5.PNG)

![Easy](http://i.minus.com/ibGG9fKbKVNlA.gif)