v1.6.0

Changelog

fc92642 Version 1.6.0
931cc1c Allow Firefox prefs to be set in config.toml
2b97b29 HTTP server: fix for stale DOM dimensions
554f7f3 Fix JS tests
31def7c Config to set custom global CSS
c7ddd91 Add Patreon to Github's sponsor button
d079f9a JS prettier fixes
f8b0e55 Text rendering: fixes and improvements