add pt_BR translation + fix preview for mumtiple domains

git-svn-id: https://plugins.svn.wordpress.org/polylang/trunk@1021766 b8457f37-d9ea-0310-8a92-e5e31aec5664
add pt_BR translation again

git-svn-id: https://plugins.svn.wordpress.org/polylang/trunk@1021768 b8457f37-d9ea-0310-8a92-e5e31aec5664