In a tough year for financial firms, Eaton Vance Corp. came out ahead of the pack in the Globe 100, ranking number one among its peers and number 13 overall. The Boston-based mutual fund firm, which has been overseeing investments since 1924, had $1.2 billion in revenue in calendar 2011, up 7 percent from the prior year despite the choppy market environment. Eaton Vance had $225 million in net income in the year (not to be confused with its fiscal year, which runs through Oct. 31), up 36 percent.