Fixes #14 [attachment] codes

#14 

This PR changes the BBCode Parser so, that it changes all attachment codes to `[attachment=o{oldid}]`. Afterwards the attachment module changes the id to the new one. The cleanup page replaces all old codes (eg missing attachment or attachment module not run) to `[ATTACHMENT NOT FOUND]`.

Also changed the vB parsers to make use of the new parser classes.