Update changelog with --show-formatters switch

Change-Id: I402ccae58c35e4c84b3a2901129c600f6f3f3af5
Reviewed-on: http://gerrit.causes.com/37743
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane@causes.com>
Tested-by: Shane da Silva <shane@causes.com>