[FEATURE] Change theme selection control to be a dropdown

[denete]

Is your feature request related to a problem?

The current button approach does not lend itself to offering more than a small handful of themes. With the idea of allowing more user-contributed themes, moving to a more compact interface would be preferred.

Describe the Solution You'd Like

Change theme selection control to be a dropdown.
Have a thumbnail of the color theme displayed in a static position when the select control changes value.

Describe Alternatives You've Considered

Buttons

Would you be willing to help implement this?

• Yes, I can submit a PR
• Yes, I can help test
• No, but I'd use it!

---

73!

[denete]

/assign

[denete]

Because the settings pane changes as a theme is selected, it may not be necessary to have a preview image or render.

[denete]

PR #708 submitted.