This patch addresses a specific Qml problem, where the meta types list
will grow indefinitely when unloading and reloading Qml components over
and over (in an failed effort to save memory).
The implementation is not specific to Qml though, but will cater to all
use-cases where registered types may not live until the application's
termination.
Change-Id: Ic0224dcd19aeb559715ef088b22a30509be2456b
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>
91dfab223a