Hide domain when post is an URL

Avant:
![Before](http://f.cl.ly/items/362c0f152l3f0q103P06/Capture%20d%E2%80%99%C3%A9cran%202013-11-12%20%C3%A0%2023.45.44.png)

Après:
![After](http://f.cl.ly/items/401B0Z0R0f1k2g2j3K1B/Capture%20d%E2%80%99%C3%A9cran%202013-11-12%20%C3%A0%2023.45.31.png)