[Sane-analysis] Update to inclusive pions wiki section

[O. A. Rondon]

I have implemented the scaling fit to the Yerevan pion photoproduction
data in my standalone version of O'Connell's epc code, replacing the
call to the Wiser parameterization, see items under "Scaling fit"
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Inclusive_pion_and_nucleon_electroproduction

The modified epc output agrees quite well with the pion
electroproduction data at 13 deg. on 12C, and it also gives competitive
agreement with Wiser for the data on protons
https://userweb.jlab.org/~rondon/sane/analysis/pairs/scalfit-photo-electro.pdf

The epc output replaces the normalized fits posted previously that
depended on a somewhat arbitrary normalization. epc correctly integrates
over the bremsstrahlung and virtual photon spectra, per eq. (5) and (6)
of O'Connell's report on inclusive pions. The epc_or_v4 FORTRAN code
handles pi+, pi- and pi0 electro and photoproduction on nuclei
https://userweb.jlab.org/~rondon/sane/analysis/pairs/epc_or_v4.f

A section on the fit errors will be added later.

Cheers,

Oscar