Fix for IQM skeletons with multiple root bones (#218)

Fix case where skeleton contains multiple root bones with no parent bone

iqm/iqm.cpp

@@ -4577,6 +4577,7 @@ void calcanimdata()
 				pose &j = poses.add();
 				j.name = p.bonename;
 				j.parent = -1;
+				if(p.boneparent >= 0) {
 					loopk(p.remap)
 					{
 						if (!strcmp(poses[k].name, fr.pose[p.boneparent].bonename))
@@ -4585,6 +4586,7 @@ void calcanimdata()
 							break;
 						}
 					}
+				}
 				loopk(10) { j.offset[k] = 1e16f; j.scale[k] = -1e16f; }
 			}