Make minor visual improvements

Changes:

 * Added `cursor: pointer;` to further indicate that the commit message title can be clicked (on my first visit, I completely missed the `Click message to expand` message, and it took me a few seconds to figure it out, especially as Firefox does not support `<details>/<summary>`, and thus, the <img src="https://f.cloud.github.com/assets/1223565/2504124/ad84155a-b389-11e3-8602-bd9ba25a23bc.png" width=20 height=20> sign is not displayed)

* Made lines easier to read by making other minor improvements.

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Web page: [before](http://operasoftware.github.io/upstreamtools/) / [after](http://jsbin.com/cejikoyu/1) (had to remove some of the content due to JS Bin [size limit](https://f.cloud.github.com/assets/1223565/2504027/ae7fb604-b388-11e3-83c5-bf847d4cdbb0.png))

Screenshots:

| Browser | Before | After |
|:---|:---|:---|
| Firefox | <img src="https://f.cloud.github.com/assets/1223565/2503997/499a8296-b388-11e3-9016-d9c9899fa300.png" width=200 height=100>  | <img src="https://f.cloud.github.com/assets/1223565/2503998/4a769dbc-b388-11e3-845d-29939d9c4c94.png" width=200 height=100>   |
| Opera | <img src="https://f.cloud.github.com/assets/1223565/2503999/4b6e6d26-b388-11e3-9adc-1485094c8979.png" width=200 height=100>  | <img src="https://f.cloud.github.com/assets/1223565/2504000/4cac3b5a-b388-11e3-8c9a-010a3176b619.png" width=200 height=100>   |


(Cc @mathiasbynens)