Special case category icons allowing use of icons with file entries
Merge branch 'master' of https://github.com/cbhaley/calibre
Implement multiple emblems for the file browser
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pep8
Fix grid view not updated immediately when marked books changed

Also fix translations for show marked books menu item.
Update National Geographic Magazine
Fix Ctrl/Shift+M shortcut not working
Refactor the file builder
Book container: Remove references to toc and raster cover from opf when those files are deleted.
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Start work on deleting files
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Amazon metadata download: Fix parsing of some dates on amazon.de

Fixes #1238125 [Download Covers: Error parsing publish date for url](https://bugs.launchpad.net/calibre/+bug/1238125)
EPUB Metadata: Implement updating identifiers

EPUB Metadata: Implementing updating identifiers in the epub file from
calibre when polishing or exporting the epub

ebook-meta: Add an --identifier option to set identifiers.
version 1.6
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Finish the implementation of delete files
Option to mark newly added books

An option to mark newly added books with a temporary mark. Optionis in
Preferences->Adding books. Fixes #1238609 [[Enhancement] Set books as "Marked" when adding](https://bugs.launchpad.net/calibre/+bug/1238609)
Handle case where cache file does not exist.