Fix * Don't call load() to load source constants; leave that up to the programmer ([`7a9e529`](https://github.com/shawwn/atomicz/commit/7a9e52957ed3cc983435923be8ada784e01c0e38))
0.3.0
Feature * Implement atomicz.fetch_{add,sub,or,xor,and} and atomicz.compare_exchange ([`fb27e64`](https://github.com/shawwn/atomicz/commit/fb27e642e1e3ef913fbbea1d2d7fa05f7c2fdc9a))