detect @import loop; fixes #315
detect @import loop; fixes #315

kkkyyy03/scssphp,leafo/scssphp,leafo/scssphp,g105b/scssphp,g105b/scssphp,dleffler/scssphp,g105b/scssphp,dleffler/scssphp,dleffler/scssphp,leafo/scssphp