The vernal equinox is still days away but Atlanta is already in springtime mode. Similarly to the blossoming trees and shrubs, farmers markets are popping with green treasures. After a long winter, there is nothing more welcoming than the first herbaceous greens and bright fruits. As chefs replace hearty brown dishes with vibrant color, Atlanta bartenders are stirring refreshing spring tonics that are aromatic and perfumed as the warm breeze…