Add Armatures module

Read and display armatures exported from Blender
Add vtkBoneWidgets, VTK widgets for bone editing and visualization
Add vtkArmatureWidget - Widget that handles the bones parent relations

Refactoring of the vtkBoneWidget that no longer know anything about
their parent beside an origin and an orientation. The referencing/calling
 of the event is handled by the vtkArmatureWidget.
Merge remote-tracking branch 'vovythevov/vtkBoneWidgets' into Armatures
Add bone and armature MRML nodes
Fix bone tree view model and persistent interaction mode
BUG: Change bone defaut values to (0, 0, 0) and (1, 0, 0)

Also sorting CMakeLists alphabetically

See bugID #0013620
ENH: Bones always displayed on top.

Sor far this enhancement does not reflects the newest VTK style.
This should be implemented in its own vtkOpenGLBoneRepresentation class.
This may be done is we decide to refactor the representation system.

Also changing the includes.

See Issue #13613
ENH: Add Name attribut for vtkBoneWidget

Issue #13615
STYLE: Bone Widget Refactoring - part 1

Harmonize function naming.

See Issue#13621
BUG: Fix SetWidgetStateToPose/Rest() mixup

See Issue#13621
BUG: Fix state checking repetition

See Issue#13621
BUG: Overall Armature fix.

1 - Add code for handling multiple top level bones.
2 - Add useful access methods.
3 - Accomodating with new vtkBoneWidget changes (most notably Name)

Modifying tests accordingly.

See Issue# 13616
Apply bone node hierarchy to armature widget
ENH: Add vtkQuaternion from VTK.
ENH: Refactor vtkBoneWidget to use vtkQuaternion
FIX: Fix Set*HeadAndTail methods
FIX: Fix representation:

Add overlay cases.
Change set display functions to take double[3] as in vtkLineRepresentation
Merge remote-tracking branch 'vovythevov/vtkBoneWidgets' into Armatures7
Armature bash commit: Connecting Bone Widget with Slicer Interface.

Conflicts:
	Modules/Loadable/Armatures/MRML/Core/vtkMRMLArmatureNode.cxx
	Modules/Loadable/Armatures/MRML/Core/vtkMRMLArmatureNode.h
	Modules/Loadable/Armatures/MRML/DisplayableManagers/vtkMRMLArmatureDisplayableManager.cxx
	Modules/Loadable/Armatures/qSlicerArmaturesModuleWidget.cxx
	Modules/Loadable/Armatures/qSlicerArmaturesModuleWidget.h