Clean up the radiative transfer part; use a super photon approach
Make nu0 a constant
Re-implementing a black body torus
Ensure the image has correct aspect ratio
Remove the assumption that the observer is in Minkowski spacetime

When we compute k^t and k^phi in src/Kerr/rsh.h, we assumed that E =
-k_t = 1.  This is only a good approximation when the observer is in
an asymptotically flat (Minkowski) spacetime.  By normalizing the
initial k^t and k^phi by 1 / E, we remove this assumption.
Taking into account redshift
Stop the photons at larger optical depth
Set infrared as the default frequency but do not use it for torus
Simple absorption formulation for testing purpose
Output final result if compiled with the options IO=0 and GL=0
Construct magnetic fields from data; put ad hoc magnetic dependence
Add an interpolation table according to grmonty
Implement emissivity j_nu and the Planck function B_nu
Implement the radiative transfer equations with ad hoc normalization

Hence the resulting image is all NAN.
Use macro for constants, rename functions and local variables
Correct the density and temperature normalization
Use dimensionless electron temperature in B_Planck()
Rearrange floating point operations to avoid underflow/overflow
In addition to nu0, let the users adjust Gamma, Tp_Te, and ne_rho

And we run out of characters so the torus radius and angular frequency
are not fixed.
Match the default parameters with our harm simulations