Added more information about project installed

Before enhancement:
![capture d ecran 2014-11-30 a 21 05 49](https://cloud.githubusercontent.com/assets/667519/5239116/bf08c954-78d4-11e4-9d46-01767681be37.png)

After enhancement:
![capture d ecran 2014-11-30 a 21 03 16](https://cloud.githubusercontent.com/assets/667519/5239124/c4fbbf88-78d4-11e4-9ef6-4e8a394229ad.png)

I'm not sure if it is a good idea that the command completely terminates only if we couldn't detect the installed Symfony version.