Blender Git Loki

Orange branch: Revived hidden treasure, the Groups!

Previous experiment (in 2000) didn't satisfy, it had even some primitive
NLA option in groups... so, cleaned up the old code (removed most) and
integrated it back in a more useful way.

Usage:
- CTRL+G gives menu to add group, add to existing group, or remove from
groups.
- In Object buttons, a new (should become first) Panel was added, showing
not only Object "ID button" and Parent, but also the Groups the Object
Belongs to. These buttons also allow rename, assigning or removing.
- To indicate Objects are grouped, they're drawn in a (not theme yet, so
temporal?) green wire color.
- Use ALT+SHIFT mouse-select to (de)select an entire group

But, the real power of groups is in the following features:

-> Particle Force field and Guide control
In the "Particle Motion" Panel, you can indicate a Group name, this then
limits force fields or guides to members of that Group. (Note that layers
still work on top of that... not sure about that).

-> Light Groups
In the Material "Shaders" Panel, you can indicate a Group name to limit
lighting for the Material to lamps in this group. The Lights in a Group do
need to be 'visible' for the Scene to be rendered (as usual).

-> Group Duplicator
In the Object "Anim" Panel, you can set any Object (use Empty!) to
duplicate an entire Group. It will make copies of all Objects in that Group.
Also works for animated Objects, but it will copy the current positions or
deforms. Control over 'local timing' (so we can do Massive anims!) will be
added later.
(Note; this commit won't render Group duplicators yet, a fix in bf-blender
will enable that, next commit will sync)

-> Library Appending
In the SHIFT-F1 or SHIFT+F4 browsers, you can also find the Groups listed.
By appending or linking the Group itself, and use the Group Duplicator, you
now can animate and position linked Objects. The nice thing is that the
local saved file itself will only store the Group name that was linked, so
on a next file read, the Group Objects will be re-read as stored (changed)
in the Library file.
(Note; current implementation also "gives a base" to linked Group Objects,
to show them as Objects in the current Scene. Need that now for testing
purposes, but probably will be removed later).

-> Outliner
Outliner now shows Groups as optio too, nice to organize your data a bit too!

In General, Groups have a very good potential... for example, it could
become default for MetaBall Objects too (jiri, I can help you later on how
this works). All current 'layer relationships' in Blender should be dropped
in time, I guess...