Python-afl

* [Bump clap-rs to fix `cargo-afl fuzz --help` bug.](https://github.com/rust-fuzz/afl.rs/issues/121)

* Implement persistent mode.
* Add docstrings for the exported functions.
* Add __version__.
* Don't rely on the Python hash() function for computing code location
identifiers.
+ Don't set PYTHONHASHSEED in py-afl-fuzz.
+ Remove the py-afl-showmap command.
afl-showmap proper can be now used for Python code.
+ Remove the AflError class. It was only used for checking PYTHONHASHSEED.
* Improve the setup script:
+ Check Cython version.
* Implement a small test suite.

-- Jakub Wilk <jwilkjwilk.net> Mon, 31 Aug 2015 16:56:12 +0200

* [Prefer panic catching strategy over adjusting panic strategy.](https://github.com/rust-fuzz/afl.rs/pull/123)
* [Incorporate commit hash into directory structure.](https://github.com/rust-fuzz/afl.rs/pull/125)

* [Print error message if archive file (to be linked) can't be found.](https://github.com/rust-fuzz/afl.rs/commit/d65c9cbc7f679aae87b0ad92d7e2496ee4e09e55)

* [Use more generic C compiler binary name](https://github.com/rust-fuzz/afl.rs/commit/f1369aadc2352510d2af42d23480324800960d26)
* [More descriptive panic messages](https://github.com/rust-fuzz/afl.rs/commit/7f0114c0a0d42e1487f5e573e949b12f8932f42c)

* Make the setup script install the py-afl-fuzz and py-afl-showmap binaries.

-- Jakub Wilk <jwilkjwilk.net> Tue, 14 Jul 2015 19:34:35 +0200