Option for border/encapsulation for standard Audio Formatter

[alliomeria]

What would be great:

An option for enabling border/encapsulation (via theme class specification) for the Strawberry Field Audio Formatter

Why this would be great:

The current AV player can be a bit difficult to interact with, depending on the size and background setup.

[DiegoPino]

The ideal here would be to allow extra CSS class for every formatter (common settings). Since Drupal Views already allows that, I feel this could be a better/seamless experience for end users.