Create flush-logs.php

-- Source inspired by Virender Bhanot comment's : http://dev.mysql.com/doc/refman/5.6/en/log-file-maintenance.html
-- Modified in order to support multiple slaves. Get the oldest log file used by all slaves in order to use it as the reference.
-- The script could be executed on any host (even another one that don't have mysql installed; this is the case for host with only Mysql installed and no PHP).
-- Remove nothing if one Slave (or Master) is down or has a problem.
-- The script assumes that bin log filenames use the default Mysql pattern (e.g. : mysql-bin.000001).
-- Settings are read from slaves.config and master.config files, one host per line with the following format: host:user:password; comments lines starting with # are ignored.
-- To display debuging information use ./flush_logs.php debug on CLI or purge_master_logs.php?debug on a web browser, by default nothing is displayed in order to avoid cron jobs send e-mails.