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.
version 2.6
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Remove use of |app| placeholder in user manual, as it causes problems with translations
Make function signature detection more robust when generating template langauge help for the User Manual.
Proper exclusion of the unused index document
Dont build the english version of themanual twice when using the --language option
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Proper exclusion for generated language based user manual files
Raise User Manual translations completion threshold
calibre-debug: support execution of a directory containing a __main__.py file
Use \ as pathsep in manual. Fixes #1382704 [Location of files on Windows system](https://bugs.launchpad.net/calibre/+bug/1382704)
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Fix regression in previous release that prevented arrow keys/tab key from working in completion popups on OSX. Fixes #1382633 [Unable to use arrow buttons](https://bugs.launchpad.net/calibre/+bug/1382633)
Nicer event debugging