fix dialog image position

On error dialog, the picture is on top of error message. In the file i changed 
```css
.elfinder-dialog-icon{
   position:absolute;
   width:32px;
   height:32px;
   left:12px;
   top:50%;
   margin-top:-15px;
   background:url("../img/dialogs.png") 0 0 no-repeat
}
```
by 
```css
.elfinder-dialog-icon{
   width:40px;
   height:32px;
   float:left;
   background:url("../img/dialogs.png") 0 0 no-repeat
}
```