[orangecontrib] rework the display for ft and kweight. kWeight is displaying nothing for the time beeing.

Everything is displayed by ft througt to 'spectrum' display: the window and the ftintensity

This require the creation of some helpers to link io and XasObject, this is the goal of xas.core.io.

[core][XasObbject] add `keep_process_flow` parameter to XasObject to automatically associate a temporary file to the XASObject process.

[core][XasObbject] add copy_process_flow_to function to copy the process flow from the current xasobject to a random hdf5 file

Add roi process and roi widget

Closes #5

See merge request workflow/xas!9

Fix 10 - make pymca process from a thread

Closes #10

See merge request workflow/xas!8

- 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.

Now if a new request is required for processing and the processing thread is running, skip the request. Simplify thing.

[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.

[gui] add advancement on the processing

See merge request workflow/xas!7

- 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

Fix 1 gui

Closes #1

See merge request workflow/xas!6

Enable to display a map or the spectrum
Spectrums are only displyed with energy and mu at the moment but should evolve with time.
Maybe we would like to do the same for the map ???

[orange add-on] use the XASObjectDialog in the input_xas. Allow to select a .dat file (single spectrum) or spectra from .hdf5