embeded files adds an extra % at the end

if you do something like  

```
+file://blah|width=50px+
```

it will become

```
<img src="..." style="width: 50px%">
```

and that generates problems in firefox (but is incorrect, anyway). 
This is probably a bug of pillar, but I do not where to report it, so I put here so we do not forget. 
