Add changes file for Qt 5.10.0

Change-Id: I8834d6703950d9c105a738e660aaa4399ac8ce4e
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>

dist/changes-5.10.0

+Qt 5.10 introduces many new features and improvements as well as bugfixes
+over the 5.9.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 5.10 series is binary compatible with the 5.10.x series.
+Applications compiled for 5.9 will continue to run with 5.10.
+
+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.
+
+****************************************************************************
+*                               Qt 5.10.0 Changes                           *
+****************************************************************************
+
+ - This release contains only minor code improvements.
+
+Third-Party Code
+----------------
+
+ - Bundled libtiff was updated to version 4.0.8+