following on from last commit r36263.

copying metaball, lattice and armature datablocks while in editmode could segfault when they were freed, NULL these pointers on copy.

source/blender/blenkernel/intern/armature.c

@@ -214,6 +214,11 @@ bArmature *copy_armature(bArmature *arm)
 	};
 	
 	newArm->act_bone= newActBone;
+
+	newArm->edbo= NULL;
+	newArm->act_edbone= NULL;
+	newArm->sketch= NULL;
+
 	return newArm;
 }
 

source/blender/blenkernel/intern/curve.c

@@ -201,6 +201,7 @@ Curve *copy_curve(Curve *cu)
 
 	cun->editnurb= NULL;
 	cun->editfont= NULL;
+	cun->selboxes= NULL;
 
 #if 0	// XXX old animation system
 	/* single user ipo too */

source/blender/blenkernel/intern/lattice.c

@@ -219,7 +219,9 @@ Lattice *copy_lattice(Lattice *lt)
 		ltn->dvert = MEM_mallocN (sizeof (MDeformVert)*tot, "Lattice MDeformVert");
 		copy_dverts(ltn->dvert, lt->dvert, tot);
 	}
-	
+
+	ltn->editlatt= NULL;
+
 	return ltn;
 }
 

source/blender/blenkernel/intern/mball.c

@@ -132,6 +132,9 @@ MetaBall *copy_mball(MetaBall *mb)
 		id_us_plus((ID *)mbn->mat[a]);
 	}
 	mbn->bb= MEM_dupallocN(mb->bb);
+
+	mbn->editelems= NULL;
+	mbn->lastelem= NULL;
 	
 	return mbn;
 }