Nieves Mec model has been changed from cross section tables to
interpolation from nuclear response functions binned each 10
MeV in energy and momentum transfer up to recommended cut of 1.2 GeV.
Tables have been calculated for carbon and oxygen nuclei.

Now all neutrino flavors are available for CC interactions in Nieves
MEC model, appropriate change in line 337 of nuwro.cc made.
Nuclei up to nitrogen calculated from carbon table,
heavier:from oxygen table.
Nieves MEC is now calculated from response functions
some code cleanups, more comments in event1.h