K-9 Mail v6.508

What's Changed

• Removed "Send…" submenu from the message view toolbar (@cketti)
• Limit summary notification actions to messages for which individual notifications are currently being displayed (@cketti)
• Fixed crash when trying to download an embedded image not using an http(s) URI (@cketti)
• Internal changes (@wmontwe, @cketti)
• Updated translations (many volunteers)

Full Changelog: 6.507...6.508