Document context for copying nodes (#305)
A bug was found in DeepCopy (or really anything that ends up copying a
node) that some nodes (such as the husband, wife or child) cannot be
created without a FamilyNode. The bug was that the FamilyNode was not
being tracked at a high enough level so duplicated nodes would not
inherit it correctly. Even though there was already code to do that, it
wasn't working correctly.
This lead to a greater look at how the APIs work and I realised that the
document must be provided in many cases because any process that
directly or indirectly needs to copy a node will need this proper
context.
Even though this patch breaks several of the existing APIs (by adding a
document parameter) none of the behaviour has changed. If you are
unsure when updating the library you should create a new document and
pass it in for that parameter.
Fixes #301
