[url] conversion - ftp:// protocol

[_Jojo_]

phpBB2 allows any kinds of resources in [url] tags, including ftp. So in phpBB2, [url=ftp://example.org]...[/url] is valid. However, SMF doesn't like it and requires special [ftp] tags - or else, the ftp links will be broken. This should be taken into account when converting posts.