CHT: Catalogue Harmonizer. Basic version

[matley]

Provide an API to allow the user to harmonize a catalogue, i.e. to convert a measure set to a target scale.

At a first stage, regression output (emsr) are used as conversion formula. Each emsr is required to convert to the target scale. So the main algorithm will look like:

Given in input:
1) a measure set `M`
2) a target scale `s`
3) an ordered vector of emsr `EMSR` (that acts as conversion formula)
4) a "strict" flag `f` (optional, default to False)

the algorithm gives in output a set of magnitude values MV in the target scale

Algorithm outline:

Initialize MV as empty
for each measure m in M:
  find the emsr in EMSR with the minumum index such that m is in native_measures(emsr)
 if an emsr is not found and f is True:
    find an emsr in EMSR such that the emsr.native_scale = m.native_scale.

  apply the model implied by emsr to m, and append the result to MV

The API could like:

E.g.

harmonizer = Harmonizer("Mw")
harmonizer.add_conversion_from_model(emsr1)
harmonizer.add_conversion_from_model(emsr2)
harmonizer.harmonize(a_measure_list)

=> returns a list of float numbers, or an associative list where the first element is a measure and the second one is the measure in the target scale