Add README.md that's missing from the 0.2.0 release
Add README.md that's missing from the 0.2.0 release

The 0.2.0 release doesn't install, because it needs a README.md file rather than README.rst, as of https://github.com/pnpnpn/timeout-decorator/commit/9f302a455aaefd0b5397d4f9f5183f22af88b2f1, and the file isn't included in the package itself. This adds it to the package (I think).
pnpnpn/timeout-decorator,yetone/timeout-decorator