mcd v2.3

Changes

• Add IGMP proto support for raw VLAN interfaces
• New mctl show mdb command
• New mctl check command to probe for required tools
• All mctl commands now run mctl check internally to ensure
  required tools are available
• Refactored logging, all log messages affected and may have been
  altered in their output, and severity
• Add configure support for setting IPC socket group ID when mcd
  creates its IPC socket, useful to provide wheel group access

Fixes

• Fix router port detection for VLAN filtering bridges
• Fix duplicate log message on send_igmp() failure
• Fix time_t -> int misuse, found by Coverity Scan
• Fix uninitialized scalars, found by Coverity Scan
• Fix resource leak, found by Coverity Scan
• Fix possible out-of-bounds write, found by Coverity Scan
• Fix possible out-of-bounds access, found by Coverity Scan
• Fix build warnings, removing unused functions and adjusting levels