Blender Git Loki

Layer drag & drop reordering

Took some time to get logic to work like user's would expect it, but seems to work now.

Use new array based iterator for object drawing

Use array for storing object bases in layers

Reading bases of a layer from file still doesn't work :/

Merge branch 'master' into soc-2016-layer_manager

Fix new layer based object drawing not used

Fix undo/redo and file read/write

Storing/reading objects assigned to layers currently crashes since there's no support for GHash read/write. Will probably change into array/listbase since GHash doesn't make much sense here anyway.

Use new, fast and simple array iterator instead of recursive iterator

Group positioning needs to be fixed after this, will check soon.

Store array of all layer items in the layer tree

Coexists with LayerTree.items and LayerTreeItem.childs listbases which were used for recursive iterations over the layer tree (using BKE_layertree_iterate or BKE_layeritem_iterate_childs). However, it was a bit annoying having to use this everywhere, especially if many args had to be passed as void *. Also, iterative methods with arrays instead of listbases should give us a bit of speedup.
It's possible LayerTree.items will not be needed anymore, but will leave in for now.

Array is only used on BKE level so far.

Merge branch 'master' into soc-2016-layer_manager

Conflicts:
source/blender/editors/interface/interface_handlers.c

Fix undo and file reading after deleting layer with content

Reduce memory allocations in layer remove operator

Cleanup: Add/correct comments

Fix compiling/viewport drawing with WITH_ADVANCED_LAYERS disabled

Cleanup: Add comments, improve naming, etc

Viewport: Draw objects by iterating over layers

Instead of iterating over all objects, we now iterate over layers and the objects inside of them. Later we can skip invisible layers, but they are not supported yet.
Objects assigned to multiple layers are currently drawn multiple times, we can avoid this (although it *might* be useful in some cases).

Since current code allows objects not being assigned to any layer, un-assigned objects are not drawn at all. To fix this you need to assign them to a layer.

Correction to previous commit

Support assigning objects to layers

Selected objects are now assigned to selected layers by pressing the M-key in the layer manager editor. Nothing visible happens then, but objects are now assigned to the layer.
Deleting a layer now invokes a popup from which the user can choose to select the layer with or without content.

Code still needs more work, but this depends on other changes. Undo/redo and file read/write doesnt' work yet, it's simply crashing.

Add common shortcuts

X/Del - Delete layers
Ctrl+G - Add selected to new group
Ctrl+N - Add new layer

Cleanup: Avoid hardcoded view coordinates

Invert layer drawing order: Top to bottom instead of bottom to top

Convention in Blender is to use top to bottom, not the other way around.