Error while rounding with printf from bc in systems with comma as decimal separator

as in line 14 /helpers/server. i.e.:

```
$ printf '%.0f' $(bc <<< "scale=2; sqrt(540^2+960^2)")
bash: printf: 1101.45: invalid number
$ printf '%.0f' 2202.90
bash: printf: 2202.90: invalid number
$ printf '%.0f' 2202,90
2203
```