[Development] Backporting the "stop unloading plugins" change to 5.6

[Edward Welbourne]

Marc Mutz
> Please don't equate 'resource' with 'memory'. Memory is just one of many
> resources a program may have acquired, and the _only_ resource which does not
> need to be released at program exit.

Open file descriptors ?
There may be others, but that's the one I tend to think of.
... and I did qualify with "that gets released on exit" language.

	Eddy.