[orangecontrib] add _ParameterWindowContainer to add a auto/manual option for computation in OW from larch and pymca

xftf fails because chi is not setted by exafs. Could it be computed from outside ?

fix 6f127e5e, process, progress.. should still be part of xas.process

- now process can take an output and an output_dict for storing the result in a multiprocessing.Proxy object
- rework process action to avoid several call to pymca `processSpectrum` function
- add an option to XasObject `to_dict` function to simply store raw data (which is the reference), but also to keep processing results to be used later.
This is need for the 'non gui' workflow processing which uses a dictionnary instead of a XasObject.

[pool process + processing thread] proto - make processing in a pool and start from a separated thread to avoid gui freeze.

Move Normalization to multiprocessing.Pool and the call from orange from a dedicated thread and with a QThreadPool.
This prevent any gui freeze.
For now this is just a prototype. Some thing to do:

- create a pool_process that will be inherited from PyMca_normalization and QPyMca_normalization.
- generalize this structure for each orange widget.

- create core/progress module which contains `Progress` class used to give some feedback about the advancement
- create orangecontrib/progress module to overwrite Progress functions with a QSignal in order to connect this processing to the orange widget.
- this require to move all core processing to classes (ft, exafs...) to keep the 'Progress' or 'QProgress' object

- simplify the bases structure Spectrum and XASObject to be more generic and continue workfing with pymca.

- simplify the bases structure Spectrum and XASObject to be more generic and continue workfing with pymca.

- create callable classes in order to get the setParameters function.
- copy parameters to the xas_obj processed.
- /close #2

[io] rework spectrum, to separate exafs and FT. Should even be other variable. Update the output configuration

[unit test] add a workflow unit test with the four first process. Should ne executed without any log error from pymca