New font options and fixes

Fixes

• Fix a retain problem in the windowing system (#336)
• Reduce display event overhead

Additions

• Add font subdomains: font.family=<string>, font.style=<string>, font.size=<float> (the size is animatable)
• Set a CONFIG_DIR environment variable which is available in all scripts and set to the directory where the sketchybarrc file is located

Full Changelog: v2.14.3...v2.14.4