This makes the following changes to summary.7.txt:
1. Preserve the sign of J_φ_peak J_φ_max, i.e. if the J_φ is negative,
those will be negative. Previously they would always be unsigned.
2. If the sign of J_φ is alternating significantly, specifically if
(∫|J_φ|dA - |∫J_φ⋅dA|) / ∫|J_φ|dA > 10%
then sign of ρ_avg_J, Δρ_avg_J, ρ_max_J, Δρ_max_J will be negative.
Previously they were always positive.
3. If there is no current J_φ=0 (power dPdV=0), then
ρ_avg_J=1, rho_max_J=1 (ρ_avg_P=1, rho_max_P=1).
Previosuly they would be set to zero.
This helps producing continuous results as a beam is gradually
focused into the plasma.
This was the final module with global variables to be rewritten.
The functionaly of pec: `pec_init`, `spec`, `postproc_profiles` has been
replaced by the `ray_projector` object in `gray_project.f90` with the
following methods: `projector%init`, `projector%project` and
`projector%statistics`.
The new code is functionally identically with only breaking change being
in Δρ_J, the full-width at max/e of the current density.
Before this change Δρ_J could be negative to signal the J_φ profile had
at least one positive and one negative peak, after the value is always
positive. Note: in either case Δρ_J was given by the largest peak only.
