cmq: lots of various fixes

[kirg]

• added new top-level shortcut commands to list extents (x), list destinations (d), cg-extents (cgx), etc
• a new "cmq fix fixdestuuid" command that updates the (newly added) 'destination_uuid' column for each row of 'consumer_groups' table, with the 'consumer_group.destination_uuid' value.
• various minor fixes in 'cmq gc'
  • use "set" package instead of 'map[string]string'
  • removed redundant variables, maps, etc.
• enhanced the 'cmqWriter' interface to make it easier to do "json" output, etc
• implemented 'listStoreExtents' and 'listInputHostExtents' commands
• moved top-level metadata args handling to 'meta.go'
• the delete and undo writers (used by 'cmq gc') creates only one "_delete.cql" and "_undo.cql" each, instead of one per table
• added support to recognize 'status' by numeric values (0 -> open, etc)
• support routines for ANSI control sequences

[thuningxu]

Can you explain what this diff does?

[CLAassistant]

All committers have signed the CLA.

[coveralls]

Coverage decreased (-0.2%) to 66.68% when pulling 63e6033635c37ffc5891576b39d0488ef8619294 on cmq-gc into 9e0668a6037ad200576b4798e128177324d099ba on master.