Finishing MLK’s work requires grassroots organizations to be proactive, not reactive, says activist Bree Newsome — As she prepared to come to Memphis, Brittany “Bree” Newsome read Dr. Martin Luther King Jr.’s last book, Where Do We Go From Here, and realized two things. First: He was prophetic. Second: The way some people regard this 50th year since his assassination is “just kind of, like, false,”…