0.6.3-ls21

LinuxServer Changes:

Add docker mod to enable optional ebook conversion on x86-64. Add unrar.
calibre-web Changes:

New feature:
Added direction settings for comic reader

Bug Fixes:
Fix not loading loading-icon
Fix magic link on python 3
Fix for reader with not supported formats
Fix instance name not shown in opds feed
fix for advanced search without "custom column 1"
Fix for non loading pdf-files in reader
Fix registration emails are shown to normal users