Move caching to src/cache/; Finalize API parsing fixes
Font and user cache code has been moved to special files, independant from src/config.rs
API parsing changes have been properly tested, and last.fm API JSON is now trace-logged for debugging convenience.
Reliable user info; Font refactor
Hit a few more endpoints to fix missing images, fallback to default album art just in case.
Refactor the font cache into its own file.
Custom font support complete
Remove redundant HTML escaping helpers.
Create plain theme, do some escaping, fix some busted envvars, document themes.
lots of stuff. theming basically done, added some logging, frontend basically done.