- [x] move fully from github to cgit
  - [x] copy the github issues to this file
  - [x] update stackoverflow links to cgit
  - [x] update app links to cgit
  - [x] add note about sending patches and remarks via email in readme

- [x] use a button to open popups (to avoid triggering popup blockers)
  - [x] confirm whether action clicks do not trigger the blocker
  - [x] remove redundant popup blocker check at start

- [x] add a donation link to the app

- [ ] Add the current local time
      (next to the timer?)

- [ ] Add a loading indicator
      (Showing that PDFJs is still loading and that the app is not ready yet).
      (Could replace the "available offline too" mention, which is a bit
      confusing anyway).

- [ ] Selectable text layer:
      Add a selectable text layer on top of the rendered canvas,
      allowing the user to copy text and click on embedded links.

- [ ] Slider overview:
      Display a thumbnails grid of all the slides to the presenter,
      making jumping between slides faster.

- [ ] Display audience slide on speaker screen:
      Display the slide shown to the audience full-screen on the speaker's
      screen when maintaining a button pressed for example.

- [ ] Highlight, pointer and spotlight:
      Add something similar to what Impressive does,
      allowing the presenter to highlight parts of the slide during the
      presentation.
      (https://impressive.sourceforge.net/)