1. Local variables are automatically deallocated when they go out of
scope.
2. When calling exit() during CLI processing some stuff wasn't being
deallocated, but it doesnt matter because the OS does it anyway.
So, get rid of it entirely.
- Replace the `get_free_unit` subroutine with the built-in
`newutin` option of the `open` statement.
- Replace `locatex` with just `locate` + an index offset.
- Replace `inside` with `contour%contains`.
- Merge `vmaxmin` and `vmaxmini` into a single subroutine
with optional arguments.
- Remove unused `range2rect`, `bubble`.
Similarly to eb648039 this change replaces the `equilibrium` module with
a new `gray_equil` module providing the same functionality without using
global variables.
- `read_eqdsk`, `read_equil_an` are replaced by a single `load_equil`
routine that handles all equilibrium kind (analytical, numerical,
and vacuum).
- `scale_equil` is merged into `load_equil`, which besides reading
the equilibrium from file peforms the rescaling and interpolation based
on the `gray_parameters` settings and the equilibrium kind.
To operate on G-EQDSK data specifically, the `change_cocors` and
`scale_eqdsk` are still available. The numeric equilibrium must then
be initialised manually by calling equil%init().
- `set_equil_spline`, `set_equil_an`, `unset_equil_spline`
are completely removed as the module no longer has any internal state.
- `fq` is replaced by `equil%safety`; `bfield` by `equil%b_field`;
`frhotor`, `frhopol` by `equil%pol2tor` and `equil%pol2tor`;
and the remaining subroutines by other methods of `abstract_equil`
retaining the old name.
- the `contours_psi` subroutine is replaced by `equil%flux_contour`,
with a slightly changed invocation but same functionality.
- the `gray_data` type is no longer required ans has been removed: all
the core subroutines now access the input data only though either
`abstract_equil`, `abstract_plasma` or the `limiter` contour.
