- 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`.
This adds a new configuration file based on the INI format.
The new format will allow adding GRAY parameters without breaking
compatibility with existing configurations, unlike as of the old
gray_params.data.
