Display of multiple authors

[wenzlawski]

In Calibre multiple authors are delimeted with an ampersand (&), such that two authors in author sort form look like "Marx, Karl & Engels, Friedrich".

This causes problems when sorting by author in calibredb.el, as it separates the authors by comma. This is done in calibredb-all-author-sort and calibredb-format-item.

Simple solution is to replace the comma in (split-string x ",") with an ampersand.

Will this be a solution or am I missing something?