Changed to reference `cheese.yml`
To prevent the following undesirable outcome for anyone playing along at home
```
spectacle -d -l test/fixtures/cheese.png test/fixtures/cheese.json
fs.js:663
return binding.open(pathModule.toNamespacedPath(path),
^
Error: ENOENT: no such file or directory, open '/usr/local/lib/node_modules/spectacle-docs/test/fixtures/cheese.json'
at Object.fs.openSync (fs.js:663:18)
at Object.fs.readFileSync (fs.js:568:33)
at Object.fetchReference (/usr/local/lib/node_modules/spectacle-docs/app/lib/resolve-references.js:66:16)
at loadData (/usr/local/lib/node_modules/spectacle-docs/index.js:55:76)
at module.exports (/usr/local/lib/node_modules/spectacle-docs/index.js:59:70)
at Object.<anonymous> (/usr/local/lib/node_modules/spectacle-docs/bin/spectacle.js:39:1)
at Module._compile (module.js:660:30)
at Object.Module._extensions..js (module.js:671:10)
at Module.load (module.js:573:32)
at tryModuleLoad (module.js:513:12)
at Function.Module._load (module.js:505:3)
at Function.Module.runMain (module.js:701:10)
at startup (bootstrap_node.js:193:16)
at bootstrap_node.js:617:3
```
