Add changes file for 3.1.1

Change-Id: Id32ed8816ee8f67ffde1daaee3fd5c2d83448f95
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@digia.com>
QtSupport: Use QTC_ASSERT instead of QTC_CHECK if needed

Change-Id: Ifa588c3a2f7d8b3417cf86b22a8ba013e4cba362
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Nikita Baryshnikov <nib952051@gmail.com>
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>