Polling fallback message help

Motivated by: #284. [ci skip]
Yes, I actually changed my mind and rewrote the section, except I ended up posting the wrong text.

The idea is to move as much as possible to the Wiki page, because:
- you're too good at this to need my approval
- it doesn't make sense for you to wait for my responses
- the README is for developers anyway, so any troubleshooting should be in the Wiki (I restructured it earlier)
- PRs are actually a bad idea for intensive reviewing of formatted text

So you can simply reduce the section(s) in the README as much as possible and instead redirect people to e.g. the "Windows" and "Mac OSX" pages in the wiki (they have links, but they don't exist yet). Feel free to reorganize things in the wiki.

As for this issue - you can just replace the text in the README with links to the Wiki, I'll commit the changes to the README and close this, and we can discuss any changes in the Wiki until you are happy with the result (I'm more than happy with the changes you mentioned above).

That way you can improve whatever you want in the Wiki and let me know if you need feedback.