[HistoryMenu] Improvements
Merge pull request #1248 from pejakm/stfx

[HistoryMenu] Improvements
Fix regression after 2a6896e57fe75bf667a12a93295bf3ea757191f6
[LocationCompleter] Support Ctrl / Shift activation of items

Ctrl activation: Opens url in new tab
Shift activation: Opens url in new window
Closes #1245

Bookmarks: Update visit count also from location completer
BookmarkItem: Added new method updateVisitCount
[BookmarksSidebar] Enable only SingleSelection in sidebar
[CodeCleanup] Use QMouseEvent::button() in mouse release events

In press/move events, use QMouseEvent::buttons() instead
[DNT] Enable sending DoNotTrack header by default
[Code] Use QTime::elapsed() for timing
[Cleanup] Use QZ_WS_X11 only for X11 specific code

In other cases, use Q_OS_UNIX for determining UNIX platform.
UNIX platfroms without X11 should benefit from this commit, including
MAC and UNIXes on Wayland.
[Building] Don't require ending slash in USE_LIBPATH and QUPZILLA_PREFIX options
[Bookmarks] HtmlImporter: Fixed filter for html files

See #1228
[Building] Use QZ_DESTDIR variable for $SRC/bin directory

Should fix problems with shadow builds.
Closes #1252
[Building] Include defines.pri after Qt modules are added

Fixes regression from 74883f8af413616bedc9defeccd2406e45827acc
Closes #1253
[AutoSaver] Rework AutoSaver so each object can use own instance

Instead of saving everything in MainApp::saveStateSlot, save each object
separately. As a result, this will save a lot of writes to disk.

Other changes includes:
Saving bookmarks also in private mode. Closes #1208
Cleanup of code
[Session] Save session to QByteArray and then write it to file

Instead of appending data to file, write all session data at once.
This should help preventing corrupting session.dat file.

Closes #1247
[CookiesTest] Make the test pass after last commit
[CodeCleanup] IconProvider now have static methods for getting icons
[Code] Create singletons with Q_GLOBAL_STATIC macro
[main.cpp] SIGPIPE is not needed to be handled in signal_handler
[QzTools] Make QzTools class and export only the class

Also fixed building on Windows