Fix T42328: Layer manager error when locking layer objects.

Own mistake in refactor prior to commit to 'main' addon repo...

Also, some general cleanup (getting rid of stupid literal use of '20' as layer num everywhere!)
and fix for 'separator' in layers UI.
More fixes.
Proper error message for DXF versions below AC1009. Users get notified that DXF files with version below AC1009 (DXF12) are not supported. This is because there is not enough documentation available for those versions. Users with files that old are kindly requested to export their projects to newer versions. In some cases it might also work to just replace AC1006 (or anything below AC1009) with AC1009 directly in the DXF.
FIX T42252: Arcs are scaled correctly now. The scale factor now also accepts comas, not only points (comas are being replaced by points internally).
Node Wrangler back in blender render and textures

Node Wrangler now works in all node tree types.
Previously it was disabled for texture nodes and for blender render
material nodes because in those node types it was giving more errors
than advantages.
Now it works everywhere.
Merge remote-tracking branch 'hm-blender/master'

* hm-blender/master:
  Node Wrangler back in blender render and textures
  FIX T42252: Arcs are scaled correctly now. The scale factor now also accepts comas, not only points (comas are being replaced by points internally).
  Proper error message for DXF versions below AC1009. Users get notified that DXF files with version below AC1009 (DXF12) are not supported. This is because there is not enough documentation available for those versions. Users with files that old are kindly requested to export their projects to newer versions. In some cases it might also work to just replace AC1006 (or anything below AC1009) with AC1009 directly in the DXF.
  More fixes.
  Fix T42328: Layer manager error when locking layer objects.
Fix T42138: division by zero in sapling addon

Note sapling code probably has other places where that kind of issues may happen,
would need a full recheck, but that's outside of scope of basic bugfix.

Patch by mangostaniko (Nikolaus Leopold) with minor changes, thanks!

Revision: D844
Fix T42416: Mocap addon: auto-scale doesn't work.

Also simplified the code. There were a few things that were explicitly coded
while there are Python builtins that perform the same operation (and do it faster).

Reviewed by mont29 (Bastien Montagne).
Fix a minor UI issue when object has animdata but no action, raise Blender version, add addon version.
align columns (for multi-drag)
Merge remote-tracking branch 'hm-blender/master'

* hm-blender/master:
  align columns (for multi-drag)
  Fix a minor UI issue when object has animdata but no action, raise Blender version, add addon version.
  Fix T42416: Mocap addon: auto-scale doesn't work.
  Fix T42138: division by zero in sapling addon
* Measure Panel - Version 0.9.1
* Fixed value update in sidebar when drawing of lines was disabled.
* Fixed display of wrong edge lengh in edit mode (context.active_object was wrong)
* Added callback removal thanks to Daniel Ashby (hopefully this finally works :-D) https://gitorious.org/blender-scripts/blender-measure-panel-script/commit/5a265e7ceb87b01ab98256c4109a9777730242c8
* PEP8 fixes
Fix T42410: FBX Import: in **some** cases, se have to ignore pre/post rotation to get valid result.

Yet another big breakthrough in FBX fantastic transformation handling! And yet another
hacking parameter to get things imported better.

Anyway, many thanks to artgolf1000 (Mingfen Wang) for finding that hack!
Merge remote-tracking branch 'hm-blender/master'

* hm-blender/master:
  Fix T42410: FBX Import: in **some** cases, se have to ignore pre/post rotation to get valid result.
  * Measure Panel - Version 0.9.1 * Fixed value update in sidebar when drawing of lines was disabled. * Fixed display of wrong edge lengh in edit mode (context.active_object was wrong) * Added callback removal thanks to Daniel Ashby (hopefully this finally works :-D) https://gitorious.org/blender-scripts/blender-measure-panel-script/commit/5a265e7ceb87b01ab98256c4109a9777730242c8 * PEP8 fixes