Freddie Mac CFO Martin Baumann, the man largely credited with cleaning up the GSE’s financial accounting, abruptly resigned this week, with no official reason for his departure or plans for the future announced. But it may be that he just needed a break after working day and night for the last three years. “I left PricewaterhouseCoopers after 33 years on March 31 of 2003, and I came here on April 2, 2003. The company said,…