Fix #1303331 [News source "NRC Handelsblad" nrc-nl-epub.recipe download URL changed](https://bugs.launchpad.net/calibre/+bug/1303331)
Edit Book: Saved searches dialog: Make the option to control where to search a little more prominent
Refactor HTML syntax highlighter too keep track of tag nesting

This is needed for the eventual implementation of inline spellcheck
Start work on managing dictionaries in calibre
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Add ISO 3166 country codes
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Implement loading of both builtin and user installed dictionaries
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Start work on dialog to manage user installed dictionaries
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Start work on adding dictionaries