MADRID (Reuters) - Pro-independence parties in Catalonia are seen in a position to keep their absolute majority of seats in regional elections on Thursday, according to an exit poll published by La Vanguardia newspaper as polling stations closed. The separatist parties were seen getting 67-71 seats in the 135-seat assembly, the poll showed. No official results have yet been published and it was unclear if final results would match the poll.  Opinion polls before the vote had shown separatists and unionists running neck-and-neck in the wealthy Spanish region.  The first official preliminary results are expected around 2100 GMT and final results after midnight. 