Created the Frame_order.test_pdb_model_pseudo_ellipse_xz_plane_tilt system test.
This checks the PDB file created by the frame_order.pdb_model user function for the pseudo-ellipse
model with a xz-plane tilt. To properly construct the coordinates, the rotate_from_Z() method was
modified to accept a rotation matrix argument to allow the geometric shape to be rotated.
