v0.2-pre

This is the first actually use-viable version. Once the library is imported, it does not reimport on next start (neither does it check for new nor changed files tho).
Double-clicking album now loads the actual album instead of a folder where the first file is located.
Text is now properly centered and shows artist under album name (formerly shown in a tooltip).
Cover art is now saved into the same file as other library data to speed up startup.