v1.2.0c

This is 1.1.2 stable with:

• in v1.2.0a
  • experimental mirroring support, see https://github.com/sysown/proxysql/blob/v1.2.0/doc/mirroring.md
• in v1.2.0b
  • re-added support for Ubuntu12
  • re-added support for debugging , issue #467
  • avoid races condition in writing/reading mysql_servers table
• v1.2.0c
  • re-implemented fast forward , issue #528