Release 0.9.0

• The generic attachment detection now double checks if the file really exists, preventing false positives
• Implemented a heuristic match to find the chat txt file in android whatsapp chat export .zip files. This solves the problem when chat names contained special characters such as / or \ or non-ascii chars.
• System messages are now handled and displayed with a dedicated style. E.g. if a participant has been added to or removed from a chat or a message has been pinned. This was a contribution by @EinzellerXD . Thanks for that!
• There was some unused, duplicate code that has been removed now.