Fixes for the unit tests of the lib.frame_order_matrix_ops module for the free rotor isotropic cone.
The S1 order parameter has been eliminated due to angles > pi/2.0 causing the frame order matrix to
be incorrectly predicted. Therefore all unit tests have been converted to use the cone opening
angle theta instead. In addition, the test_compile_2nd_matrix_iso_cone_free_rotor_disorder had been
modified to pass with the incorrect frame order matrix by comparing to the half cone frame order
matrix rather than the identity frame order matrix.
