Blender Git Loki

Update unittests

Outliner: Support drag & drop of GROUP_INTERNAL collections

Outliner: Support enable/disable group collections and fix select icon

You can select only non-group collections.

RNA: allow for enable/disable of group collections

Remove assert from BKE_layer_collection_get_active_ensure

If all collections are group collections, we still need to create a
ew collection to accomodate new objects.

Assert on IDProp merge routine to simplify debug process

Improve debug printing for layers evaluation

Integrate group PRE processing to depsgraph

Something to check with Sergey:
What happens if the group is instanced AND is in a layer collection?
In this case we need to test something different than LIB_TAG_DOIT for
building groups and their relations.

Move group sub-collection evaluation tp DEG

Fix memleak when creating groups

Fix build in release

Fixup for 2/3: rna_layer.c

Initial group unittests

See if creating groups is working, and if it has the same structure and values
of original collection.

Fixup for 1/3: dont write groupobjects

RNA: layer_collection.create_group()

Fixup UI for 1/3

Python RNA for group collections

More work for 3/3 (aka 3.5/3)

Groups and collections 3/3

This allows you to create a group from a collection.
It is i the Menu when you click in the collections in the Outliner.

Groups and collections 2/3

This allow a new collection of type "Group". To add it hold shift when creating a
new collection in a view layer.

Note: This introduces a big hack because I couldn't get Depsgraph to behave as I
wanted. Look for DEG_COLLECTION_GROUP.

Pending tasks:
* Prevent drag and drop of collections that belong to a group unless:
** The group is local
** The source and destination are from the same group
* Prevent changing any of a group nested collections values if the group is lib
* Disable selectability for group collections

Coming next:
* Allow creation of groups from collection
** This will replace the collection with a Group collection with the newly
created group.