SANFORD For months, Republican Thom Tillis’ Senate campaign touted his accomplishments and focused his attacks on Democratic incumbent Kay Hagan, acting like a frontrunner with his eye on November. Now, in the final days before the May 6 primary, Tillis is changing his strategy. Last week, he mailed a flier to voters that attacked his top GOP rival for not paying his property taxes on time. He also debuted a TV ad that trumpets his opposition to abortion and same-sex marriage. Tillis hit the social conservative issues Saturday in his speech at the 2nd Congressional District GOP convention in Sanford....