Log Message:
calibre: update to 3.23.0.

- version: 3.23.0
  date: 2018-05-04

  new features:
    - title: "Kobo driver: Add support for new firmware"

    - title: "Book polishing: Add an option to upgrade EPUB 2 to EPUB 3"

    - title: "DOCX Input: Convert text written with dingbat fonts such as \ 
Wingding or Symbol correctly."

    - title: "When choosing the page to use as a cover from a PDF file, add \ 
a button to render more pages, if needed"

    - title: "TXT Input: Add support for embedded images that use relative \ 
URLs when converting markdown or textile. Note that this will only work if you \ 
are converting using the ebook-convert command line tool as the main calibre \ 
program moves files around, so relative references will not be valid."

    - title: "Edit book: Insert special character: Add an option to select \ 
if searching should match all words or any of the words"

    - title: 'Edit book: Insert special character: When searching by name match \ 
prefixes in addition to whole words. So you can now type "horiz" to \ 
match "horizontal".'

    - title: "Linux installer: Simplify the command used to install calibre \ 
and add support for Ubuntu 18.04 which is missing a default python \ 
executable"

    - title: "When upgrading EPUB 2 to EPUB 3 add the 'epub' namespace to \ 
all HTML files, for convenience."

  bug fixes:
    - title: "Edit Book: Fix an error caused by a landmark entry in EPUB 3 \ 
files that has an <a> tag without an href attribute."

    - title: "Edit Book: Fix names for some control characters not being \ 
displayed in the status bar"

    - title: "Searching: Fix A (B) not being treated as A AND (B)"

    - title: "Kobo driver: Add an option to not maintain bookmarks/read \ 
status/etc. when resending a book already on the device."

    - title: "DOCX Input: Ignore complex script font styles. Fixes \ 
conversion of documents that specify only complex script styles and no simple \ 
script styles."

    - title: "When updating EPUB 2 to EPUB 3 ensure only a single dc:date \ 
element is present in the OPF"