Two Central Massachusetts communities are welcoming new police chiefs. On Friday, Steven D. Giannini was sworn in as the new chief of the Fitchburg Police Department, while on Jan. 21, Thomas A. Calouro was sworn in as the new chief of the Sutton Police Department. Giannini is replacing Police Chief Ernest F. Martineau, who announced his retirement in October. Giannini started his new position on Saturday. Martineau served 37 years on the Fitchburg Police Department, including 10 years as chief. Calouro replaces Police Chief Dennis J. Towle, who announced his retirement in July. Calouro was preceded by acting Police…..