Thanks to Médéric Boquien.

It's a dictionnary to hold the spectral lines associated with the SED.
We use a disctionnary to be able to differentiate several sets of lines
(e.g. lines from old and young populations).

TODO: Complete the code to add the line contributions to the integrated flux.

Rename lumin_contributions to luminosities and use a 2 axis numpy array
instead of a list of arrays. This should accelerate some operations.

The star formation history is now stored in its own property.
TODO: maybe automatically add age and instantaneous SFR to the info dictionnary when setting the SFH.

To perform the convolution with the SFH, the rate of ionizing  photons
must not be stored as the log of its value.

The best SED must pass through the redshift/IGM module before being
saved/plotted.

Using Gyr leads to some errors when comparing times (because they are no
really equals when they shoud). So we switch to the use of Myr as it is
the precision for our times.

Maybe later, we'll go further and use integers for these values.

Rename it to dustatt_calzleit in preparation of a power law module.

* Multiplicate the Calzetti-Leitherer continuum by a power law.
* Add a UV bump.
* The luminosity under 91.2 nm to 0.
* Extrapolate the continuum over 2200 nm until attenuation reach 0.

Oops, this should have been corrected a long time ago.

By default, an exception is raised when adding an existing key to the
info dictionary. Make it possible to bypass this, for instance to add
age if we want to combine various SFH.

If we redshift a SED using a module, we must not redshift the wavelength
to compute the λ, Fν array tuple. Thus we make it optional and not
default.

Convert the warehouse a its own module and use submodules for each
"back-end".
Also, make the back-end configurable with a parameter of the psum
analysis module.

It's better (for now) to use only get_from_cache and get None when the
object is not cached.

As there is a specific module to redshift the spectrum, do not
automatically apply the redshift when computing a flux.

The redshifting module must be separated from the main modules producing
the restframe SED, because the redshift parameter is taken directly from
the observation list.
Nevertheless, it is still a SED creation module because one may want to
use it for testing various redshifts.

Simplify some module names:
dh2002_ir > dh2002
sfh_2exp > sfh2exp

Rename m2005_sfh to m2005 as it does not deal with the star formation
history.

The Marasont 2005 module is modified to use the output of a star
formation history module. The SFH is now a complete SFR vs time tuple
(taken from the SED information dictionary) and the age of the galaxy is
defined by this SFH (the maximum time).
The Maraston 2005 data class is also changed to make the convolution in
such SFH.

Instead of writing all the computation table at once, write one table
per observation as a FITS file.