Added directory with Wiscombe's scattering code

Original source can be found at:
ftp://climate1.gsfc.nasa.gov/wiscombe/Single_Scatt/Homogen_Sphere/Exact_Mie/
RDI1MACH.f was found at:
ftp://climate1.gsfc.nasa.gov/ridgway/Multiple_Scatt/DISORT2.0beta/