Feature request: jump previous/next stations in a folder using keyboard buttons

[sispus]

Sorry for my english.
It would be good to change stations in the limits of a folder using prev. and next buttons on keyboard.

Expected Behavior

Gradio should change the stations pushing "next" and "previous" buttons.

Current Behavior

Gradio couldn't use audio buttons other than play-pause.

Steps to Reproduce

Detailed Description

In steps, I want to:

1. While listening "A" station placed in "A" folder,
2. Push the "next" or "previous" button on keyboard.
3. Gradio will skip the station to the next or previous station respectively if it exists in the A folder.
4. If the station is out of the folders, that is, say, it is in the "root" folder, then gradio will play respectively the next or the previous station if it exists in the "root" folder.