removed form-group

there is already a form-group. when using "form-horizontal" class, there is an additional substraction of 15px margin on both sides of the element caused by

```
.form-horizontal .form-group {
   margin-left: -15px;
   margin-right: -15px;
}
```

![image](https://cloud.githubusercontent.com/assets/241080/3131296/e5c3000e-e802-11e3-95d5-1ddf5555c627.png)