NEW MILFORD — Hours after receiving the keys to Town Hall, Mayor Pete Bass called for a Town Council meeting Monday to deliberate whether his predecessor’s last-minute appointments to town boards are valid. Acting Town Attorney Matt Grimes, who was hired Friday, contends in a written opinion that a special meeting scheduled this week by outgoing Mayor David Gronbach was illegal because he did not identify any “exigent circumstances” that allowed him to call it with less than three days’ notice.