Merge remote-tracking branch 'origin/5.8' into 5.9

Change-Id: Ia62c820c6b312288f2ec49a0e105c0bc6edad259

dist/changes-5.8.0

+Qt 5.8 introduces many new features and improvements as well as bugfixes
+over the 5.7.x series. For more details, refer to the online documentation
+included in this distribution. The documentation is also available online:
+
+  http://doc.qt.io/qt-5/index.html
+
+The Qt version 5.8 series is binary compatible with the 5.8.x series.
+Applications compiled for 5.7 will continue to run with 5.8.
+
+Some of the changes listed in this file include issue tracking numbers
+corresponding to tasks in the Qt Bug Tracker:
+
+  https://bugreports.qt.io/
+
+Each of these identifiers can be entered in the bug tracker to obtain more
+information about a particular change.
+
+****************************************************************************
+*                          Library                                         *
+****************************************************************************
+
+ - This release contains only minor code improvements.