Update QtSensor changelog for 5.2

Change-Id: I22dbe4447c14c48bfc812cc8fb5543d5f0fa872f
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Merge remote-tracking branch 'origin/release' into stable

Change-Id: I61deffeb7b61a4157b9ecb77de35f08d47c4e9bd
Fix code snippet in Qt Sensors QML Types documentation.

Change-Id: I5639fb872b8e41cc5c5b5968cf1ddf7e247961e2
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>