Add 4 modified Bessel and 1 spherical Bessel operators

[Kanya-Mo]

• [x] special_modified_bessel_i0.out
• [x] special_modified_bessel_i0
• [x] special_modified_bessel_i1.out
• [x] special_modified_bessel_i1
• [x] special_modified_bessel_k0.out
• [x] special_modified_bessel_k0
• [x] special_modified_bessel_k1.out
• [x] special_modified_bessel_k1
• [x] special_spherical_bessel_j0.out
• [x] special_spherical_bessel_j0

[xytintel]