bin/hydiomatic.hy: Only run the main body if --name-- is __main__

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
bin/hydiomatic.hy: Support --experimental in non-diff mode too

When running in non-diff mode, respect the --experimental setting too.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>