Comparison operations aren't considered valid in function arguments #39

$ python -c 'print((1,2) == (1,2))'
True
$ cargo run -- -c 'print((1,2) == (1,2))'
    Finished dev [unoptimized + debuginfo] target(s) in 0.07s
     Running `/home/daniel/personal_dev/RustPython/target/debug/rustpython -c 'print((1,2) == (1,2))'`
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: "UnrecognizedToken { token: Some((15, EqEqual, 16)), expected: [\"\\\")\\\"\", \"\\\",\\\"\", \"\\\"in\\\"\", \"\\\"|\\\"\"] }"', libcore/result.rs:945:5
note: Run with `RUST_BACKTRACE=1` for a backtrace.