Blender Git Loki

Merge branch 'master' into datablock_idprops

Cleanup, minor fixes and serious simplification of idprops.c

Mostly, get rid of id_(un)register, we can just use mere id_us_plus/min
as anywhere else in code now. Also, unlink function was not actually
used.

Fix missing handling of IDProps of nodetree's IO sockets.

Fix mistake with last master merge...

Merge branch 'master' into datablock_idprops

Merge branch 'master' into datablock_idprops

Conflicts:
source/blender/blenloader/intern/readfile.c

Cleanup: remove 'generic' ID liblink function in readfile.c

We do need some generic ID handling refactor here (as was recently done
for writefile.c), but this out of scope of this patch - and not the way
to do it.

Merge branch 'master' into datablock_idprops

Fix obvious mistake in logic of two functions recursively handling IDProps.

They were expecting IDP_group as parameter, but then recursiveley
calling themselves with IDProps from groups and arrays, which can be of
any type...

Fix bad auto-generated UI for ID IDProps.

`RNA_path_resolve()` tries to 'dereference' pointer properties, was not
a problem before but now that we do have pointer IDProps we want to get
property here, not it's pointed data.

Cleanup and minor changes.

No functional change expected, mostly:
* Some renaming, bit of style editing, cleanup...
* Removing some useless diff from master.

Merge branch 'master' into datablock_idprops

Datablock ID Properties

Summary:
The absence of datablock properties "will certainly be resolved soon as the need for them is becoming obvious" said the [[http://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.67/Python_Nodes|Python Nodes release notes]]. So this patch allows Python scripts to create ID Properties which reference datablocks.
This functionality is implemented for `PointerProperty` and now such properties can be created with Python.

In addition to the standard update callback, `PointerProperty` can have a `poll` callback (standard RNA) which is useful for search menus. For details see the test included in this patch.

Original author: @artfunkel

Alexander (Blend4Web Team)

Reviewers: brecht, artfunkel, mont29

Subscribers: poseidon4o, mont29, homyachetser, Evgeny_Rodygin, AlexKowel, yurikovelenov, fjuhec, sharlybg, cardboard, Asticles, duarteframos, blueprintrandom, a.romanov, BYOB, disnel, aditiapratama, bliblubli, dfelinto, lukastoenne

Maniphest Tasks: T37754

Differential Revision: https://developer.blender.org/D113