In practice this means that handlerton is now created by the server and is passed to the engine. Plugin startups can now also control how plugins are inited (and can optionally pass values). Bit more flexibility to those who want to write plugin interfaces to the database.
Plugins now when compiled or not compiled work correctly with status variables.
Status variables from plugins now set their own names (removed bit where plugin name was pre-appended this broke Innodb and Cluster)
A few Makefile cleanups.
