Fix for issue searching and documentation updates.

[JNRowe]

As nvie rightly pointed out in my other pull request, I hadn't added any documentation for my changes... here that is.

I've also fixed issue searches for multiple words. I only spotted the problem as a result of adding the entry to README.rst, so I should probably learn something from that ;)

Finally, there is some slight reformatting of the documentation. Most of the text was wrapped at ~80 characters and code samples indented 4 spaces, the final commit just makes that consistent across the rest of the documentation. I realise that may be controversial, but wrapped or not wrapped it should at least be consistent.

Thanks,

James

[nvie]

Thanks for the docs and the patch!

Cheers,
Vincent