Upgrade pyo3 to 0.10.1

[messense]

pyo3 0.10 added catch_unwind! macro to prevent panics crossing ffi boundaries PyO3/pyo3#797 , which resolves #5, although ideally we should define some specific exceptions, but hey at least it's not unsound anymore.

In [1]: import cramjam

In [2]: cramjam.snappy_decompress(b'abcdefgh')
thread '<unnamed>' panicked at 'called `Result::unwrap()` on an `Err` value: Custom { kind: Other, error: StreamHeader { byte: 97 } }', src/snappy.rs:21:35
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
---------------------------------------------------------------------------
PanicException                            Traceback (most recent call last)
<ipython-input-2-1d4c0e441753> in <module>
----> 1 cramjam.snappy_decompress(b'abcdefgh')

PanicException: called `Result::unwrap()` on an `Err` value: Custom { kind: Other, error: StreamHeader { byte: 97 } }

[milesgranger]

Fantastic, thank you! I agree, it was something on the back-burner to fix and add better exception handling. 👍 As you've stated this resolved #5, I've made a different issue for this in #7