Escape control character also prevents detection in utf-8 

The following has no encoding detected:

``` python
u'\u020d\x1b'.encode('utf-8')
```

Again, not a length issue. Padding with ascii doesn't change anything. The initial character _is_ needed, I believe purely because it prevents the fix in #63 from applying by preventing the string from being considered as ascii.

Behaviour is present in 9e419e9b411a15e26c5542968b6daa3fbb4c672d
