Added specific Einstein puzzle rules for "if other ppl drink other drinks, then this person drink a specific drink e.g. tea"
Added specific Einstein rules for "if other people smoke other brands, this person smoke some specific brand"
Added specific Einstein rules for "if other ppl have different nations, then this person has a specific nation , e.g. Britsh"
Added logic to check if any precondition will be contradictory with any other subgoals.