Add more replace functionality

For my personal use, I needed to generate a page for examples that I host on my site. However when making the new example folder with the necessary files, the assets would be pointing to the wrong path. `options.replaceStrings` to the rescue. The other two options were just for completeness since `removeScripts` was already there.

```
options: {
    // Remove link tags
    removeLinkTags: true,

    // Remove meta tags
    removeMetaTags: true,

    // Replace arbitrary parts of the html
    replaceStrings: [
        {'this': 'will get replaced by this'},
        {'/old/path/': '/new/path'}
    ]
}
```