MP1-4333 : Fix WM_POWERBROADCAST messages to pass to the plugins
MP1-4333 : Rework handling based on code review comment.
Merge remote-tracking branch 'remotes/origin/MP1-4333-BUG-Not_all_WM_POWERBROADCAST_messages_are_passed_to_plugins' into Master_1.7.0Pre-Release
WIP : Bump MP.Plugins.* to 1.7 Pre_Release.