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

[gui][XASObjectViewer] move all plot function in the XasObjectViewer.py and for some function add a "mean", "std" display if possible

[orangecontrib] fix, add missing widget icons in setup.py since orangecontrib.xas.widgets.larch and orangecontrib.xas.widgets.pymca have been created

[orangecontrib] normalization work

See merge request workflow/xas!17

- orange signal 'spectra' is renamed xas_obj
- update to the new orange way to define Input and Output
- add a converter widget to convert from xas object to data table

'Spectroscopy add on' compatibility

See merge request workflow/xas!16

Unit test pymca larch

See merge request workflow/xas!15

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

Larch usability

See merge request workflow/xas!14

Add larch process orange contrib

Closes #6

See merge request workflow/xas!13