[Wiki] Update release notes for 1.6.1
[Wiki] Update release notes for 1.6.1

Change-Id: Iec24b6c412c98d3c07f82a53efde80414f5e1d76

bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr