bugfix: pass book_id to FileType plugins on postimport instead of __builtins__.id()

I have written a FileType plugin which automatically converts scanned PDF ebooks to DJVU on import to the library. the plugin needs to be given a book_id from the library's database in order to add the DJVU formatted-file to it, but the postimport dispatcher is calling the plugin with python object id's instead. I have been using a workaround to grab index (the book_id) but I'd like the upstream fixed so I can release my plugin.

thanks for the greatness that is Calibre
-joey

PS. I know there is an excellent conversion plugin framework but it is useless for scanned PDF's that have little or no markup that can be saved in intermediate HTML.