Results 2 issues of Andron

![image](https://user-images.githubusercontent.com/8457664/51747785-8ee73100-20bb-11e9-8b8f-8b75bb777f2e.png) Proposed solution: add ability to add classes and a default class for all galleries

![image](https://github.com/bard/emacs-run-command/assets/8457664/c4df8a5f-1522-4a2c-bea3-19b168a5495f) should do ![image](https://github.com/bard/emacs-run-command/assets/8457664/055e113a-e8b0-4961-9bb8-4aadfd6736b3) but instead i get ![image](https://github.com/bard/emacs-run-command/assets/8457664/60e6fa77-fe3b-49b8-a8f4-975bd3f4b0f4) pinned package at 22844ae959ec for now

stale