macOS known issues

[bengarrett]

• [x] No audio in Safari by default because Autoplay - Stop Media With Sound is set under page settings. Create a notification and link to safari user guide.
• [x] Fullscreen mode doesn't work in Safari or Chrome. But does work on Firefox. If it cannot be fixed, then detect the OS plus the browser string and disable.
• [x] Device pixel ratio causes the canvas to render incorrectly, it is only a quarter of the expected size. (see attachment)
• [x] The default browser fonts do not render the more eclectic glyphs.

[bengarrett]

Done