Large volume of warnings when using RayFlare

[phoebe-p]

Not a specific bug, but there are a large number of warnings (deprecation warnings and others) when using some RayFlare functions. This is quite annoying, and the deprecation warnings should also be dealt with.

• xarray/core/indexes.py:234: FutureWarning: Passing method to Float64Index.get_loc is deprecated and will raise in a future version. Use index.get_indexer([item]
• rayflare/matrix_formalism/multiply_matrices.py:165: RuntimeWarning: invalid value encountered in true_divide
  norm = per_bin/(1-np.exp(-alphas[:, None]*d/abscos[None, :]))
  (nan and inf are produced here)
• rayflare/matrix_formalism/multiply_matrices.py:165: RuntimeWarning: divide by zero encountered in true_divide
  norm = per_bin/(1-np.exp(-alphas[:, None]*d/abscos[None, :]))
• rayflare/rayflare/matrix_formalism/multiply_matrices.py:170: RuntimeWarning: invalid value encountered in multiply
  a_x = ((alphas[i1]*norm[i1])/(abscos))[None,:]*np.exp(-alphas[i1]*depths[:,None]/abscos[None, :])
• rayflare/rayflare/matrix_formalism/multiply_matrices.py:178: RuntimeWarning: invalid value encountered in true_divide
  scale = np.nan_to_num(A/check)
• rayflare/ray_tracing/rt.py:1182: VisibleDeprecationWarning: Creating an ndarray from ragged nested sequences (which is a list-or-tuple of lists-or-tuples-or ndarrays with different lengths or shapes) is deprecated. If you meant to do this, you must specify 'dtype=object' when creating the ndarray.
  corner = r_a - tri.P_0s
• rayflare/ray_tracing/rt.py:1198: VisibleDeprecationWarning: Creating an ndarray from ragged nested sequences
  intersn = r_a + t * d
• rayflare/ray_tracing/rt.py:1182: VisibleDeprecationWarning: Creating an ndarray from ragged nested sequences
  corner = r_a - tri.P_0s
• rayflare/ray_tracing/rt.py:1198: VisibleDeprecationWarning: Creating an ndarray from ragged nested sequences
  intersn = r_a + t * d