'arithmetic operation overflowed' when reading "-0" as JSON

[tonyg]

Running this program:

extern crate serde_json;
fn main() {
    serde_json::from_str::<serde_json::Value>("-0").unwrap();
}

causes:

thread '<main>' panicked at 'arithmetic operation overflowed', [...]/.cargo/registry/src/github.com-88ac128001ac3a9a/serde_json-0.6.0/src/de.rs:289

whereas I expected it to run to completion successfully with no output.

[nixpulvis]

See #35

[erickt]

This was closed in #35.