Featurerequest: use ebook title and checksum instead of filename to store position

[Glog78]

I use a calibre server to have my ebooks stored. I use lynx to search throu them and than hand them over to epr. In this case the file gets a random name each time i at least restart my pc. this renders the currently used implementation how epr stores the last reading position useless. I thought a little about it and maybe the following would be an idea:

Instead of using the file name to identify a file use the ebook title + a checksum of the file.