[1.0.x] Pin pyScss==1.2.x, for now.

Please see the discussion in
<https://github.com/Kronuz/pyScss/issues/265#issuecomment-58728712>.

Reviewed-By: Antoine Catton <acatton@fusionbox.com>
(cherry picked from commit 9f27a0ec7cc4de9cab5d222ca1011cc0968a579e)
Release 1.0.4