Comments option doesn't work

```
gulp.src(scssSources)
.pipe(compass({
comments: true,
css: env + '/assets',
sass: 'development/assets/scss',
})
.on('error', gutil.log))
.pipe(gulp.dest(output_dir + 'assets/'))
```

Comments won't appear in the output compiled file.

Reproduce the issue using the gulp.src and compass configuration shown in the report, then trace how the gulp-compass plugin passes the comments option into compilation. Verify the fix by compiling the sample SCSS and confirming that comments appear in the generated CSS.

Written by the indexing model from the issue text.