convert.py: Optimize "Fnu_to_Tb()" and "Sb_to_Tb()"

* Optimize the "Fnu_to_Tb()" and "Sb_to_Tb()" functions by explicitly
  calculating the conversions, avoiding the slow `astropy.unit`
  conversions (which is rather slow).  The new fast functions are named
  as "Fnu_to_Tb_fast()" and "Sb_to_Tb_fast()".
* Optimize the new functions using `numba.jit` further.
* Add `numba` to the dependencies.

1 files changed, 1 insertions, 0 deletions

diff --git a/setup.py b/setup.py
index b7725e3..1fce5c6 100755
--- a/setup.py
+++ b/setup.py
@@ -80,6 +80,7 @@ setup(
     ],
     install_requires=[
         "numpy",
+        "numba",
         "scipy",
         "pandas",
         "astropy",