Bug 1381323: composite columns aren't links in book details
Book details panel: Fix custom columns built from other columns with tag like values not clickable in the book details panel. Fixes #1381323 [Custom Column build from other columns does not show up as clickable](https://bugs.launchpad.net/calibre/+bug/1381323)

Merge branch 'master' of https://github.com/cbhaley/calibre
AZW3 Output: Ignore invalid attribute names in the input document rather than aborting the conversion on them.
E-book viewer: Allow right clicking on the toolbar buttons to popup the optional menus, useful when using the viewer on a touch screen. Fixes #1380359 [Feature Request: right-click menus missing in ebook viewer](https://bugs.launchpad.net/calibre/+bug/1380359)
Allow configuring a keyboard shortcut to toggle highlighting of search results via Preferences->Keyboard (under Miscellaneous). Fixes #1380528 [[Enhancement]  Keyboard Shortcut To Toggle Search Highlighting](https://bugs.launchpad.net/calibre/+bug/1380528)
Add output profile and welcome wizard entries for upcoming Kindle Voyage
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Kobo driver: Update to support new firmware from Kobo. Fixes #1382051 [Kobo: Skip modifying epub if no valid CSS rules and bump firmware version](https://bugs.launchpad.net/calibre/+bug/1382051)

Skip modifying epub if no valid CSS rules and bump firmware version

While looking at a problem with the stylesheet on Kobo devices recently,
I realised that if the modify CSS option was set and the was no file, it
still modified the stylesheet. Now, will not do this if there are no
valid rules in the kobo_extra.css file.

Also bumping firmware version to 3.11.1. Kobo are about to release an
update. They big jump on version number is to match the desktop
application version.