Tray troubleshooting previously only showed apt, which is wrong on Fedora and Arch. Document AppIndicator install for Debian/Ubuntu, Fedora, and Arch in INSTALL.md and the website troubleshooting page. Fixes #570
Tray troubleshooting previously only showed apt, which is wrong on Fedora and Arch. Document AppIndicator install for Debian/Ubuntu, Fedora, and Arch in INSTALL.md and the website troubleshooting page. Fixes #570