Theme not working with the latest documentationjs code

I get the following error when using this theme with the latest documentationjs code.

```
docs/node_modules/documentation/lib/commands/build.js:60
throw err;
^

TypeError: theme is not a function
at Object.makeHTML [as html] (docs/node_modules/documentation/lib/output/html.js:21:3)
at onDocumented (docs/node_modules/documentation/lib/commands/build.js:63:47)
at docs/node_modules/documentation/index.js:101:7
at docs/node_modules/documentation/lib/input/dependency.js:45:5
at ConcatStream. (docs/node_modules/documentation/node_modules/concat-stream/index.js:36:43)
at emitNone (events.js:72:20)
at ConcatStream.emit (events.js:166:7)
at finishMaybe (docs/node_modules/documentation/node_modules/concat-stream/node_modules/readable-stream/lib/_stream_writable.js:475:14)
at endWritable (docs/node_modules/documentation/node_modules/concat-stream/node_modules/readable-stream/lib/_stream_writable.js:485:3)
at ConcatStream.Writable.end (docs/node_modules/documentation/node_modules/concat-stream/node_modules/readable-stream/lib/_stream_writable.js:455:41)
```

Inizia leggendo il percorso delle chiamate documentato in docs/node_modules/documentation/lib/output/html.js e docs/node_modules/documentation/lib/commands/build.js, quindi confronta come viene fornito il theme al codice documentationjs più recente. Il lavoro è completato quando il theme genera la documentazione senza l’errore segnalato “theme is not a function”.

Scritto dal modello di indicizzazione a partire dal testo della issue.