Nested objects writable by default

Change-Id: Ie407eab0b600310a6da1ab462b2ba1bf636368c4
Unit tests

Change-Id: I7b21710826b2404d233e176c7efb9b373f49ee5f
Doco

Change-Id: If94a0d00b70b19caa7ff74fa9673d0d96ad30c42