Added number input field to gain and pan so users can enter a precise value

[Asomeones222]

This should solve issue #41 . I tested it on multiple websites and it seemed to work fine, I'd be happy if we can discuss these changes.

Note I tried to maintain the formatting of the code, but it was kinda difficult without any formatting config file in the project, however, I did maintain almost all of it.

Let me know what you think!

[Asomeones222]

Done. you could check if these are all the necessary changes

[Asomeones222]

Fixed indentation, this should cover all the necessary changes

[valpackett]

Thanks! I'll look into releasing an update soon.