Polling fallback message help

Motivated by: #284. [ci skip]
I had the same thought about having a WIKI page. I could not find a good page to link to. I do like your thought on adding simplified instructions though. Why not add a 4th-level heading at the bottom of my additions that looks like:

---

#### Simplified [Bundler](http://bundler.io/#getting-started) and [Sass](http://sass-lang.com/) example

1. Create a `Gemfile` with these lines:

 ```ruby
source 'https://rubygems.org'
gem 'listen', '~> 2.8'
gem 'sass'
```

1. Next, use Bundler to update gems:

 ```bash
$ bundle update
$ bundle exec sass --watch # ... or whatever app is using Listen.
```