Fix database icons license issues.

Pull C62_Tux.png, C63_Feather.png, C64_Apple.png, C65_Apple.png
and C65_W.png from the latest KeePass 2 version.

Replace C68_BlackBerry.png with another icon from openclipart.org.
It's unclear where this KeePass 2 icon is from.

Closes #69