Added ability to define app name, author, price and icon via the meta tag

This allows developers to add data- attributes to the meta tag to populate title, author, price and icon. I've added the checks between the options hash and checking the other items on the page.

Example: 
```
<meta content="app-id=org.example.app" data-author="Author Name" data-icon="/path/to/icon.png" data-title="Example App" name="google-play-app" />
```