[geary: 13/13] Fix HTML, CSS, MIME and other artifiacts appearing in previews. Bug 714317.

[Michael Gratton <mjog src gnome org>]

commit 1ad02284bd67ca02cef22bf4edfbe99298346696
Merge: f8c2a9a 7654b16
Author: Michael Gratton <mike vee net>
Date:   Sun Dec 25 10:42:50 2016 +1030

    Fix HTML, CSS, MIME and other artifiacts appearing in previews. Bug 714317.
    
    Also works around conversation message preview being too short
    on wide (4K) screens. Bug 772607.
    
    Merge branch 'bug/714317-hide-html-in-preview'

 .../conversation-list/conversation-list-store.vala |   10 +-
 .../conversation-viewer/conversation-list-box.vala |    1 -
 .../conversation-viewer/conversation-message.vala  |   11 +-
 src/engine/api/geary-email.vala                    |   14 +-
 .../imap-engine/imap-engine-email-prefetcher.vala  |   18 +-
 src/engine/imap/api/imap-folder.vala               |   81 ++-
 src/engine/rfc822/rfc822-message-data.vala         |   81 +--
 src/engine/rfc822/rfc822-message.vala              |   33 +-
 src/engine/rfc822/rfc822-utils.vala                |   85 +++-
 src/engine/rfc822/rfc822.vala                      |    5 +-
 src/engine/util/util-html.vala                     |  185 +++---
 test/CMakeLists.txt                                |    4 +
 test/engine/rfc822-message-data-test.vala          |  622 ++++++++++++++++++++
 test/engine/rfc822-message-test.vala               |   32 +
 test/engine/rfc822-utils-test.vala                 |   44 ++
 test/engine/util-html-test.vala                    |  100 ++++
 test/main.vala                                     |    9 +
 17 files changed, 1120 insertions(+), 215 deletions(-)
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