Empty string gets parsed as 0

[DaniPopes]

Uint::<_, _>::from_str("") always parses successfully as 0.

[prestwich]

this appears to be @recmo 's intended behavior, as is the parser uses from_base_be and there is no BaseConverError::NoDigits. We could add one in 2.0.0 if we feel there's a compelling reason?

[u59149403]

We could add one in 2.0.0 if we feel there's a compelling reason?

Please, add. Current implementation violates principle of least surprise. It doesn't match parse::<u32> behavior