OptionParser Dropping Arguments

I'm trying to run a script in Distillery, which under the covers runs:

`elixir -e Mix.Releases.Runtime.Control.main --logger-sasl-reports false -- eval --mfa MyApp.run/1 --argv -- --my-arg-1 --my-arg-2`

However, in `post_process_command/3`, after parsing `eval` with it's options "mfa" and "argv" correctly, we hit the "else" case, which causes us to incorrectly parse the rest of the args after the `--`. In the case above, the args are dropped, but even in the case of non-hyphenated args, the behavior is inconsistent (as it's trying to parse them as further commands).

I suggest that we either a) dispatch immediately after parsing a command, instead of `arguments changed during option parsing, so go back to parse_args`, or b) allow users to input some value that causes command to stop processing and dispatch with the args.

Option b could work as:

`elixir -e Mix.Releases.Runtime.Control.main --logger-sasl-reports false -- eval --mfa MyApp.run/1 --argv --extra --my-arg-1 --my-arg-2`

When the algorithm sees `--extra`, it dispatches the rest of the argv instead of continuing to process.

Happy for thoughts on this.

Start at post_process_command/3 and reproduce the shown `elixir -e Mix.Releases.Runtime.Control.main` command, including `eval`, `--mfa`, `--argv`, and arguments after `--`. Define and implement a dispatch behavior that preserves the remaining argv instead of dropping it or treating it as further commands; done means both hyphenated and non-hyphenated arguments are passed through consistently.

Written by the indexing model from the issue text.