Second fix for sidebar glitch and page artifact

This fix has been tested on `Google Chrome Version 34.0.1847.137` / `Ubuntu 12.04`

**synopsis:** The CSS and page structure were not designed to have a `sidebar` inside a `content`, a `sidebar` should be at the same level as a `content`. In the case of the builds page (which renders an ember app), this caused a situation where the page structure was: 
```
#content
    #sidebar
    #content
```
This commit fixes the duplicate ID usage and the CSS glitch for the sidebar.

**note:** the testing has been done using middleman server
**note:** the `before` pictures represents the state of the page prior to the last glitchy commit which introduced an additional bug, the `after` represents the state after all the new changes

**Before / After**

![1_compare](https://cloud.githubusercontent.com/assets/1452653/3422549/39951da6-ff4c-11e3-8ae2-e0faa9af2902.jpg)
![2_compare](https://cloud.githubusercontent.com/assets/1452653/3422550/3c80d0a0-ff4c-11e3-9cd5-8e540a48754e.jpg)
![3_compare](https://cloud.githubusercontent.com/assets/1452653/3422551/3ef62a42-ff4c-11e3-9892-c8ff166d8ae8.jpg)
![4_compare](https://cloud.githubusercontent.com/assets/1452653/3422552/435cdb80-ff4c-11e3-8556-d3d7314374b6.jpg)
![5_compare](https://cloud.githubusercontent.com/assets/1452653/3422553/46a19d8a-ff4c-11e3-8d00-3d191fe6fd83.jpg)