Fixes #6

Close but what do you think about something like this? 

```ruby
return @settings if defined?(@settings)
results = YAML.load(ERB.new(File.read('ab_panel.yml')).result)
@settings = results ? results.symbolize_keys : nil
```

then you skip the YAML load every time, and is a bit easier to read imho without the double `||=`.