`SyntaxWarning: invalid escape sequence '\w'`

Sardine now prints the following message when booting:
```python
<unknown>:1: SyntaxWarning: invalid escape sequence '\w'
<unknown>:1: SyntaxWarning: invalid escape sequence '\s'
```
As far as I know, there is no part of the init process printing special characters. This has to be investigated. These warnings might raise an error in future versions...