Armature Selection Improvements.

- Added a check to make sure Armature is valid.
- Added a helper to select the current armature  selected in armature selection.
- Added a helper to get all meshes.
- Updated all current functions to work with the system.

ui/quick_access.py

@@ -22,7 +22,6 @@ class AvatarToolkitQuickAccessPanel(bpy.types.Panel):
         layout = self.layout
         layout.label(text=t("Quick_Access.options"))
 
-        # Add Armature Selection
         layout.prop(context.scene, "selected_armature", text="Select Armature")
 
         row = layout.row()