EPUB Input: If the EPUB file identifies an actual cover image in
addition to the titlepage html file, use the cover image instead of
rendering the titlepage. This is faster and has the advantage that an
EPUB to EPUB conversion preserves internal cover structure.
Comments editor: The Insert Link button has no effect until the user
clicks inside the comments box, therefore disable it until it is ready,
to prevent confusion. Fixes#1208073 [Insert Link not working](https://bugs.launchpad.net/calibre/+bug/1208073)
Allow adding multiple books to an already running calibre by passing
multiple file arguments to calibre.exe. Also change the .desktop file in
linux to indicate calibre can accept file arguments. Fixes#1207518 [Calibre is invisible in Ubuntu 13.04 "Open with" dialog](https://bugs.launchpad.net/calibre/+bug/1207518)
Kobo driver: Add an option to modify the styling in books being sent to
the device, based on a template on the device. Fixes#1207151 [Append and modify CSS when sending epubs to Kobo devices](https://bugs.launchpad.net/calibre/+bug/1207151)
This allows users to have a "kobo_extra.css" file in the root of their
device containing CSS rules. This will be appended to all stylesheets in
the epub. As well, if the extra rules contain an @page rule, any
existing @page rules will be stripped from the stylesheets. Finally, if
any of the extra rules include "widows" and "orphans" settings, these
are stripped from the rules in the stylesheets.
When downloading metadata from Amazon, convert the amazon categories into
tags. You can turn this off by going to Preferences->Metadata download
and configuring the Amazon source. Fixes#1206763 [[Enhancement] Get tags from Amazon](https://bugs.launchpad.net/calibre/+bug/1206763)
Fix renaming a user category to the same name it already has erases the
user category. Fixes#1207131 [Renaming a user category to the same name it already has erase this same user category](https://bugs.launchpad.net/calibre/+bug/1207131)
