USR2 will now reopen *all* log files (like Unicorn). Also, the logfile will be reopened using IO#reopen rather than creating a new Logger object, reducing the possibility of having a stale logger object
Adds USR2 changes
Merge pull request #1467 from ctaintor/improve_log_reopening

USR2 will now reopen *all* log files (like Unicorn)
Clean up log rotation code