Support mouse back button
Environment
- Lollypop version: 1.0.5
- GTK+ version: 3.24.2
- Operating system: Debian 9
Feature
There are a few places in the UI where you can go "back". When clicking on an album, or an artist, for example. The UI shows a back button on the top-left corner, and "Alt + Left Arrow" works to go back. It would be nice the mouse back button (usually button 8) could also do the same.