Adam Easton BBC Warsaw correspondent WOJTEK RADWANSKI/AFP There are two front-runners among the 13 candidates: Rafal Trzaskowski (R) and Karol Nawrocki When Poles vote for a new president on Sunday, they are expected to set up a second round run-off between Warsaw’s liberal mayor Rafal Trzaskowski and national-conservative historian Karol Nawrocki. If opinion polls are...