By Renee Maltezou ATHENS (Reuters) - Greece's leftist Syriza party has pulled 5 points clear of conservative New Democracy as general elections draw near, according to a poll on Friday that gave the clearest lead to either of the two main rivals in 18 surveys. The parties have been neck-and-neck in the run-up to the Sept. 20 election, with all other polls published this month showing a gap of 1 percentage point or less. But Friday's ProRata poll in left-leaning daily newspaper Efimerida ton Syndakton put Syriza, led by former prime minister Alexis Tsipras, on 28. ...