Improved psydac api
- Removed DOF comparison in mhd ops tests.
- Added transpose mhd operators (also for X1 and X2, which needed the creation of the ProductFemspace H1xH1xH1).
- Updated xx_test_psydac_basics to pytest all analytical mappings.
- Investigate the indexing of Stencilvectors and ._data attribute.
- Added a folder for analytic functions
- Added fields.py which contains the class Fields_init to initialize FE fields in any code.
- Started maxwell_psydac, works until DATA saving.
- Added *.hdf5 to .gitignore.
- Added schur solver class.
- Added wrappers for LinearOperators (prod, sum ,diff).
- Added Push_maxwell_psydac class.