Orange request; Bones in Armature now have own layer settings.

Works like for Object layers, but local within Armature itself. Each Bone
can be in (16 now) any layer, and the Armature layer defines what is
visible or not. Also note that hiding will still work too.

Since the Blender code is *stuffed* with Bone options now, this commit
requires a good test if all tools we got now comply to layers...
(I counted 130 cases for checking for selected Bones in code!)

In PoseMode; hotkey M will show 'movetolayer' menu. Not in editmode...
then its the mirror menu.

Todo: make action/nla drawing comply to Armature layer settings.

source/blender/src/drawobject.c

@@ -4126,5 +4126,52 @@ void draw_object_backbufsel(Object *ob)
 	}
 
 	myloadmatrix(G.vd->viewmat);
-
 }
+
+
+/* ************* draw object instances for bones, for example ****************** */
+/*               assumes all matrices/etc set OK */
+
+void draw_object_instance(Object *ob, int dt)
+{
+	DerivedMesh *dm=NULL, *edm=NULL;
+	int needsfree= 1;
+	
+	if(ob==NULL || ob->type!=OB_MESH) return;
+	
+	if(G.obedit && ob->data==G.obedit->data)
+		edm= editmesh_get_derived_base();
+	else 
+		dm = mesh_get_derived_final(ob, &needsfree);
+		
+	if(dt<=OB_WIRE) {
+		if(dm)
+			dm->drawEdges(dm, 1);
+		else if(edm)
+			edm->drawEdges(edm, 1);	
+	}
+	else {
+		if(dm)
+			init_gl_materials(ob);
+		else {
+			glEnable(GL_COLOR_MATERIAL);
+			BIF_ThemeColor(TH_BONE_SOLID);
+			glDisable(GL_COLOR_MATERIAL);
+		}
+		
+		glLightModeli(GL_LIGHT_MODEL_TWO_SIDE, 0);
+		glFrontFace((ob->transflag&OB_NEG_SCALE)?GL_CW:GL_CCW);
+		glEnable(GL_LIGHTING);
+		
+		if(dm)
+			dm->drawFacesSolid(dm, set_gl_material);
+		else if(edm)
+			edm->drawMappedFaces(edm, NULL, NULL, 0);
+		
+		glDisable(GL_LIGHTING);
+	}
+
+	if(edm) edm->release(edm);
+	if(dm && needsfree) dm->release(dm);
+}
+