- for now tests fails with larch but this come from larch (issue at the workfonw parametrization)

- add `outputs` and `inputs` entries in processing classes used in ppfaddon aliases file.
- add `get_xas_obj` function in est.app.utils module
- mode est.app.utils._convert_spectra_dims to public

close #16

Signed-off-by: payno <henri.payno@gmail.com>

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

- we can convert .ows to a gui free workflow.
- user can give input and output file to overwrite the one existing in xas.

./bootstrap.py xas process pymca_workflow.ows -i /usr/share/pymca/EXAFS_Cu.dat -o ./output.h5